Environmental art

From Wikipedia, the free encyclopedia

https://en.wikipedia.org/wiki/Environmental_art 

 

Marco Casagrande, Sandworm, Beaufort04 Triennial of Contemporary Art, Wenduine, Belgium, 2012

Environmental art is a range of artistic practices encompassing both historical approaches to nature in art and more recent ecological and politically motivated types of works. Environmental art has evolved away from formal concerns, for example monumental earthworks using earth as a sculptural material, towards a deeper relationship to systems, processes and phenomena in relationship to social concerns. Integrated social and ecological approaches developed as an ethical, restorative stance emerged in the 1990s. Over the past ten years environmental art has become a focal point of exhibitions around the world as the social and cultural aspects of climate change come to the forefront.

The term "environmental art" often encompasses "ecological" concerns but is not specific to them. It primarily celebrates an artist's connection with nature using natural materials. The concept is best understood in relationship to historic earth/Land art and the evolving field of ecological art. The field is interdisciplinary in the fact that environmental artists embrace ideas from science and philosophy. The practice encompasses traditional media, new media and critical social forms of production. The work embraces a full range of landscape/environmental conditions from the rural, to the suburban and urban as well as urban/rural industrial.

History: landscape painting and representation

Claude Monet, Waterloo Bridge, London

It can be argued that environmental art began with the Paleolithic cave paintings of our ancestors. While no landscapes have (yet) been found, the cave paintings represented other aspects of nature important to early humans such as animals and human figures. "They are prehistoric observations of nature. In one-way or another, nature for centuries remained the preferential theme of creative art." More modern examples of environmental art stem from landscape painting and representation. When artists painted onsite they developed a deep connection with the surrounding environment and its weather and brought these close observations into their canvases. John Constable's sky paintings "most closely represent the sky in nature". Monet's London Series also exemplifies the artist's connection with the environment. "For me, a landscape does not exist in its own right, since its appearance changes at every moment; but the surrounding atmosphere brings it to life, the air and the light, which vary continually for me, it is only the surrounding atmosphere that gives subjects their true value."

Diane Burko, Waters Glacier and Bucks, 2013

Contemporary painters, such as Diane Burko represent natural phenomena—and its change over time—to convey ecological issues, drawing attention to climate change. Alexis Rockman's landscapes depict a sardonic view of climate change and humankind's interventions with other species by way of genetic engineering.

Challenging traditional sculptural forms

Robert Morris, Observatorium, Netherlands

The growth of environmental art as a "movement" began in the late 1960s and early 1970s. In its early phases it was most associated with sculpture—especially Site-specific art, Land art and Arte povera—having arisen out of mounting criticism of traditional sculptural forms and practices that were increasingly seen as outmoded and potentially out of harmony with the natural environment.

In October 1968, Robert Smithson organized an exhibition at Dwan Gallery in New York titled “Earthworks.” The works in the show posed an explicit challenge to conventional notions of exhibition and sales, in that they were either too large or too unwieldy to be collected; most were represented only by photographs, further emphasizing their resistance to acquisition. For these artists escaping the confines of the gallery and modernist theory was achieved by leaving the cities and going out into the desert.

”They were not depicting the landscape, but engaging it; their art was not simply of the landscape, but in it as well.” This shift in the late 1960s and 1970s represents an avant garde notion of sculpture, the landscape and our relationship with it. The work challenged the conventional means to create sculpture, but also defied more elite modes of art dissemination and exhibition, such as the Dwan Gallery show mentioned earlier. This shift opened up a new space and in doing so expanded the ways in which work was documented and conceptualized.

Entering public and urban spaces

Andrea Polli, Particle Falls, 2013

 

John Fekner, Toxic, Long Island Expressway, Maspeth, Queens, NY 1982

Just as the earthworks in the deserts of the west grew out of notions of landscape painting, the growth of public art stimulated artists to engage the urban landscape as another environment and also as a platform to engage ideas and concepts about the environment to a larger audience. While this earlier work was mostly created in the deserts of the American west, the end of the 1970s and the beginning of the 1980s saw works moving into the public landscape. Artists like Robert Morris began engaging county departments and public arts commissions to create works in public spaces such as an abandoned gravel pit. Herbert Bayer used a similar approach and was selected to create his Mill Creek Canyon Earthworks in 1982. The project served functions such as erosion control, a place to serve as a reservoir during high rain periods, and a 2.5 acre park during dry seasons. Lucy Lippard's groundbreaking book, on the parallel between contemporary land art and prehistoric sites, examined the ways in which these prehistoric cultures, forms and images have "overlaid" onto the work of contemporary artists working with the land and natural systems.

In 1965, Alan Sonfist introduced a key environmentalist idea of bringing nature back into the urban environment with his first historical Time Landscape sculpture, proposed to New York City in 1965 and revealed to the public in 1978 in a mature, grown state. Time Landscape remains visible to this day at the corner of Houston and LaGuardia in New York City's Greenwich Village. The work resulted in a "slowly developing forest that represents the Manhattan landscape inhabited by Native Americans and encountered by Dutch settlers in the early 17th century."

Environmental art also encompasses the scope of the urban landscape. Pioneering environmental artist, Mary Miss began creating art in the urban environment with her 1969 installation, Ropes/Shore, and continues to develop projects involving extended communities through City as a Living Laboratory. Agnes Denes created a work in downtown Manhattan Wheatfield - A Confrontation (1982) in which she planted a field of wheat on the two-acre site of a landfill covered with urban detritus and rubble. The site is now Battery Park City and the World Financial Center, a transformation from ecologic power to economic power.

In 1974, Bonnie Sherk created The Farm in San Francisco, a 7-acre urban garden in underused spaces below freeway overpasses. The farm, until 1980, also served as a community center and art space the provided internships, childhood ecoart education for children, and served as a public park during its six-year existence.

Andrea Polli's installation Particle Falls made particulate matter in the air visible in a way that passersby could see. For HighWaterLine Eve Mosher and others walked through neighborhoods in at-risk cities such as New York City and Miami, marking the projected flood damage which could occur as a result of climate change and talking with residents about what they were doing.

Starting in the 2010's "guerilla gardener" Ron Finley began planting edible gardens in the urban neighborhood of South Central Los Angeles along narrow strips of dirt between the curb and sidewalk. His motivation was to address the effects of the food apartheid in certain neighborhoods including his own, and to encourage healthy eating habits, especially among children.

Ecoart

Main article: Ecological art

 

Milton Becerra, NIDOS, Táchira River, Venezuela 1995.

Ecological art, also known as ecoart, is an artistic practice or discipline proposing paradigms sustainable with the life forms and resources of our planet. It is composed of artists, scientists, philosophers and activists who are devoted to the practices of ecological art. Historical precedents include Earthworks, Land Art, and landscape painting/photography. Ecoart is distinguished by a focus on systems and interrelationships within our environment: the ecological, geographic, political, biological and cultural. Ecoart creates awareness, stimulates dialogue, changes human behavior towards other species, and encourages the long-term respect for the natural systems we coexist with. It manifests as socially engaged, activist, community-based restorative or interventionist art. Ecological artist, Aviva Rahmani believes that "Ecological art is an art practice, often in collaboration with scientists, city planners, architects and others, that results in direct intervention in environmental degradation. Often, the artist is the lead agent in that practice."

There are numerous approaches to ecoart including but not limited to: representational artworks that address the environment through images and objects; remediation projects that restore polluted environments; activist projects that engage others and activate change of behaviors and/or public policy; time-based social sculptures that involves communities in monitoring their landscapes and taking a participatory role in sustainable practices; ecopoetic projects that initiate a re-envisioning and re-enchantment with the natural world, inspiring healing and co-existence with other species; direct-encounter artworks that involve natural phenomena such as water, weather, sunlight, or plants; pedagogical artworks that share information about environmental injustice and ecological problems such as water and soil pollution and health hazards; relational aesthetics that involve sustainable, off-the-grid, permaculture existences. 

There is discussion and debate among ecoartists regarding whether ecological art should be considered a discrete discipline within the arts, distinct from environmental art. A current definition of ecological art, drafted collectively by the EcoArtNetwork is "Ecological art is an art practice that embraces an ethic of social justice in both its content and form/materials. Ecoart is created to inspire caring and respect, stimulate dialogue, and encourage the long-term flourishing of the social and natural environments in which we live. It commonly manifests as socially engaged, activist, community-based restorative or interventionist art." The global community ArtTech NatureCulture, which convenes over 400 creative practitioners engaged in ecological art forms across disciplines, states: "In precarious times, how can we build new ways forward that challenge and transform the many inequalities of the status quo? Our ways of addressing this are as diverse as our backgrounds, but we are united by a shared interest in using creative practices across disciplines (from arts, design, culture and hacking to science, technology and activism) to explore alternative futures that rethink, rebuild and heal." Co-founder Kit Braybrooke has described the reason for ArtTech NatureCulture as "alone, we face climate grief and instability, but together, we rebuild."

Artists who work in this field generally subscribe to one or more of the following principles: focus on the web of interrelationships in our environment—on the physical, biological, cultural, political, and historical aspects of ecological systems; create works that employ natural materials or engage with environmental forces such as wind, water, or sunlight; reclaim, restore, and remediate damaged environments; inform the public about ecological dynamics and the environmental problems we face; revise ecological relationships, creatively proposing new possibilities for coexistence, sustainability, and healing.

Contributions by women in the area of EcoArt are significant. Many are cataloged in WEAD, Women Environmental Artists Directory founded in 1995 by Jo Hanson, Susan Leibovitz Steinman and Estelle Akamine. The work of ecofeminist writers inspired early male and female practitioners to address their concerns about a more horizontal relationship to environmental issues in their own practices. The feminist art writer Lucy Lippard, writing for the Weather Report Show she curated in 2007 at the Boulder Museum of Contemporary Art, which included many environmental, ecological and ecofeminist artists, commented on how many of those artists were women.

Considering environmental impact

Robert Smithson, Spiral Jetty, 2005

 

herman de vries, Sanctuarium, Leibfriedschen Garten, Stuttgart, 2013

Within environmental art, a crucial distinction can be made between environmental artists who do not consider the possible damage to the environment that their artwork may incur, and those whose intent is to cause no harm to nature. For example, despite its aesthetic merits, the American artist Robert Smithson's celebrated sculpture Spiral Jetty (1969) inflicted permanent damage upon the landscape he worked with, using a bulldozer to scrape and cut the land, with the spiral itself impinging upon the lake. Similarly, criticism was raised against the European sculptor Christo when he temporarily wrapped the coastline at Little Bay, south of Sydney, Australia, in 1969. Conservationists' comments attracted international attention in environmental circles and led contemporary artists in the region to rethink the inclinations of land art and site-specific art.

Sustainable art is produced with consideration for the wider impact of the work and its reception in relationship to its environments (social, economic, biophysical, historical, and cultural). Some artists choose to minimize their potential impact, while other works involve restoring the immediate landscape to a natural state.

British sculptor Richard Long has for several decades made temporary outdoor sculptural work by rearranging natural materials found on site, such as rocks, mud and branches, which will therefore have no lingering detrimental effect. Chris Drury instituted a work entitled "Medicine Wheel" which was the fruit and result of a daily meditative walk, once a day, for a calendar year. The deliverable of this work was a mandala of mosaicked found objects: nature art as process art.

Leading environmental artists such British artist and poet, Hamish Fulton, Dutch sculptor Herman de Vries, the Australian sculptor John Davis and the British sculptor Andy Goldsworthy similarly leave the landscape they have worked with unharmed; in some cases they have revegetated damaged land with appropriate indigenous flora in the process of making their work. In this way the work of art arises out of a sensitivity towards habitat.

Perhaps the most celebrated instance of environmental art in the late 20th century was 7000 Oaks, an ecological action staged at Documenta during 1982 by Joseph Beuys, in which the artist and his assistants highlighted the condition of the local environment by planting 7000 oak trees throughout and around the city of Kassel.

Ecological awareness and transformation

Other eco-artists reflect on our human engagement with the natural world, and create ecologically informed artworks that focus on transformation or reclamation. Ecoart writer and theoretician Linda Weintraub coined the term, "cycle-logical" to describe the correlation between recycling and psychology. The 21st century notion of artists' mindful engagement with their materials harkens back to paleolithic midden piles of discarded pottery and metals from ancient civilizations. Weintraub cites the work of MacArthur Fellow Sarah Sze who recycles, reuses, and refurbishes detritus from the waste stream into elegant sprawling installations. Her self-reflective work draws our attention to our own cluttered lives and connection to consumer culture. Brigitte Hitschler's Energy field drew power for 400 red diodes from the to-be-reclaimed potash slag heap upon which they were installed, using art and science to reveal hidden material culture.

Ecological artist and activist, Beverly Naidus, creates installations that address environmental crises, nuclear legacy issues, and creates works on paper that envision transformation. Her community-based permaculture project, Eden Reframed remediates degraded soil using phytoremediation and mushrooms resulting in a public place to grow and harvest medicinal plants and edible plants. Naidus is an educator having taught at the University of Washington, Tacoma for over ten years, where she created the Interdisciplinary Studio Arts in Community curriculum merging art with ecology and socially engaged practices. Naidus's book, Arts for Change: Teaching Outside the Frame is a resource for teachers, activists and artists. Sculptor and installation artist Erika Wanenmacher was inspired by Tony Price in her development of works addressing creativity, mythology, and New Mexico's nuclear presence. Oregon based artist and arborist Richard Reames uses grafting techniques to produce his works of arborsculpture and arbortecture. He uses time-based processes of multiple plantings of trees that are then shaped by bending, pruning, grafting, in ways that are similar to pleaching and espalier. These works have ecological advantages including carbon dioxide sequestration, habitat creation and climate change mitigation.

Renewable energy sculpture

Ralf Sander, World Saving Machine III, MoA Museum of Art, Seoul, South Korea

Renewable energy sculpture is another recent development in environmental art. In response to the growing concern about global climate change, artists are designing explicit interventions at a functional level, merging aesthetical responses with the functional properties of energy generation or saving. Practitioners of this emerging area often work according to ecologically informed ethical and practical codes that conform to Ecodesign criteria. Andrea Polli Queensbridge Wind Power Project is an example of experimental architecture, incorporating wind turbines into a bridge's structure to recreate aspects of the original design as well as lighting the bridge and neighbouring areas. Ralf Sander's public sculpture, the World Saving Machine, used solar energy to create snow and ice outside the Seoul Museum of Art in the hot Korean summer.

Public art

From Wikipedia, the free encyclopedia

https://en.wikipedia.org/wiki/Public_art 

 

The Spire of Dublin

Public art is art in any media whose form, function and meaning are created for the general public through a public process. It is a specific art genre with its own professional and critical discourse. Public art is visually and physically accessible to the public; it is installed in public space in both outdoor and indoor settings. Public art seeks to embody public or universal concepts rather than commercial, partisan or personal concepts or interests. Notably, public art is also the direct or indirect product of a public process of creation, procurement, and/or maintenance.

Independent art created or staged in or near the public realm (for example, graffiti, street art) lacks official or tangible public sanction has not been recognized as part of the public art genre, however this attitude is changing due to the efforts of several street artists. Such unofficial artwork may exist on private or public property immediately adjacent to the public realm, or in natural settings but, however ubiquitous, it sometimes falls outside the definition of public art by its absence of public process or public sanction as "bona fide" public art.

Characteristics of public art

Nanas by Niki de Saint Phalle in Hanover, Germany

Common characteristics of public art are public accessibility, public realm placement, community involvement, public process (including public funding); these works can be permanent or temporary. According to the curator and art/architecture historian, Mary Jane Jacob, public art brings art closer to life.blic accessibility: placement in public space/public realm

Public art is publicly accessible, both physically and/or visually. When public art is installed on privately owned property, general public access rights still exist.

Public art is characterized by site specificity, where the artwork is "created in response to the place and community in which it resides" and by the relationship between its content and the public. Cher Krause Knight states that "art's publicness rests in the quality and impact of its exchange with audiences ... at its most public, art extends opportunities for community engagement but cannot demand particular conclusion,” it introduces social ideas but leaves room for the public to come to their own conclusions.

Public process, public funding

Public art is often characterized by community involvement and collaboration. Public artists and organizations often work in conjunction with architects, fabricators/construction workers, community residents and leaders, designers, funding organizations, and others.

Public art is often created and provided within formal "art in public places" programs that can include community arts education and art performance. Such programs may be financed by government entities through Percent for Art initiatives.

Longevity

Some public art is planned and designed for stability and permanence. Its placement in, or exposure to, the physical public realm requires both safe and durable materials. Public artworks are designed to withstand the elements (sun, wind, water) as well as human activity. In the United States, unlike gallery, studio, or museum artworks, which can be transferred or sold, public art is legally protected by the Visual Artists Rights Act of 1990 (VARA) which requires an official deaccession process for sale or removal.

Forms of public art

Mildred Howard's "The House That Will Not Pass for Any Color Than its Own" in Battery Park City, New York City

The following forms of public art identify to what extent public art may be physically integrated with the immediate context or environment. These forms, which can overlap, employ different types of public art that suit a particular form of environment integration.

• stand alone: for example, sculptures, statues, structures
• integrated (into façades, pavements, or landscapes): for example, bas reliefs, Hill figure, Geoglyph, Petroglyph, mosaics, digital lighting
• applied (to a surface): for example, murals, building-mounted sculptures
• installation (where artwork and site are mutually embedded): for example, transit station art
• ephemeral (or non-permanent): performances, temporary installations: for example, a precarious rock balance or an instance of colored smoke.

History of public art

Wolf Vostell Ruhender Verkehr / Stationary traffic, Cologne, 1969

United States, 20th century

In the 1930s, the production of national symbolism implied by 19th century monuments starts being regulated by long-term national programs with propaganda goals (Federal Art Project, United States; Cultural Office, Soviet Union). Programs like President Roosevelt's New Deal facilitated the development of public art during the Great Depression but was wrought with propaganda goals. New Deal art programs were intended to develop national pride in American culture while avoiding addressing the faltering economy. Although problematic, New Deal art programs such as FAP altered the relationship between the artist and society by making art accessible to all people. The New Deal program Art-in-Architecture (A-i-A) developed percent for art programs, a structure for funding public art still utilized today. This program allotted one half of one percent of total construction costs of all government buildings to the purchase of contemporary American art for them. A-i-A helped solidify the policy that public art in the United States should be truly owned by the public. It also promoted site-specific public art.

The approach to public art radically changed during the 1970s, following the civil rights movement's claims on public space, the alliance between urban regeneration programs and artistic efforts at the end of the 1960s, and revised ideas of sculpture. Public art acquired a status beyond mere decoration and visualization of official national histories in public space. Public art became much more about the public. This perspective was reinforced in the 1970s by urban cultural policies, for example the New York-based Public Art Fund and urban or regional Percent for Art programs in the United States and Europe. Moreover, public art discourse shifted from a national to a local level, consistent with the site-specific trend and criticism of institutional exhibition spaces emerging in contemporary art practices.

Environmental public art

La Joute by Jean-Paul Riopelle, an outdoor kinetic sculpture installation with fire jets, fog machines, and a fountain in Montreal.

Between the 1970s and the 1980s, gentrification and ecological issues surfaced in public art practice both as a commission motive and as a critical focus by artists. The individual, Romantic retreat element implied in the conceptual structure of Land art, and its will to reconnect the urban environment with nature, is turned into a political claim in projects such as Wheatfield – A Confrontation (1982) by American artist Agnes Denes, as well as in Joseph Beuys’ 7000 Oaks (1982). Both projects focus on the increase of ecological awareness through a green urban design process, bringing Denes to plant a two-acre field of wheat in downtown Manhattan and Beuys to plant 7000 oaks coupled with basalt blocks in Kassel, Germany in a guerrilla or community garden fashion. In recent years, programs of green urban regeneration aiming at converting abandoned lots into green areas regularly include public art programs. This is the case for High Line Art, 2009, a commission program for the High Line, derived from the conversion of a portion of railroad in New York City; and of Gleisdreieck, 2012, an urban park derived from the partial conversion of a railway station in Berlin which hosts, since 2012, an open-air contemporary art exhibition.

The 1980s also witnessed the institutionalization of sculpture parks as curated programs. While the first public and private open-air sculpture exhibitions and collections dating back to the 1930s aimed at creating an appropriate setting for large-scale sculptural forms difficult to show in museum galleries, installations such as Noguchi's garden in Queens, New York (1985) reflect the necessity of a permanent relationship between the artwork and its site.

This relationship also develops in Donald Judd’s project for the Chinati Foundation (1986) in Texas, which advocates for the permanent nature of large-scale installations whose fragility may be destroyed when re-locating the work.

Sustainability and public art

The Gangsta Gardener, Ron Finley, in one of his public food gardens

Public art faces a design challenge by its very nature: how best to activate the images in its surroundings. The concept of “sustainability” arises in response to the perceived environmental deficiencies of a city. Sustainable development, promoted by the United Nations since the 1980s, includes economical, social, and ecological aspects. A sustainable public art work would include plans for urban regeneration and disassembly. Sustainability has been widely adopted in many environmental planning and engineering projects. Sustainable art is a challenge to respond the needs of an opening space in public.

In another public artwork titled "Mission leopard" was commissioned in 2016 in Haryana, India, among the remote deciduous terrain of Tikli village a team coordinated by Artist Hunny Mor painted two leopards perched on branches on a water source tank 115 feet high. The campaign was aimed to spread awareness on co-habitation and environmental conservation. The art work can be seen from several miles across in all directions.

Ron Finley's work as the Gangsta Gardener (or Guerrilla Gardener) of South Central L.A. is an example of an artist whose works constitute temporary public art works in the form of public food gardens that addresses sustainability, food security and food justice.

Andrea Zittel has produced works, such as Indianapolis Island that reference sustainability and permaculture with which participants can actively engage.

Interactive public art

Public sculpture that is also a musical instrument (hydraulophone) by Steve Mann, which the public can play.

Some public art is designed to encourage direct hands-on interaction. Examples include public art that contain interactive musical, light, video, or water components. For example, the architectural centerpiece in front of the Ontario Science Centre is a fountain and musical instrument (hydraulophone) by Steve Mann where people can produce sounds by blocking water jets to force water through sound-producing mechanisms. An early and unusual interactive public artwork was Jim Pallas' 1980 Century of Light in Detroit, Michigan of a large outdoor mandala of lights that reacted in complex ways to sounds and movements detected by radar (mistakenly destroyed 25 years later). Another example is Rebecca Hackemann's two works The Public Utteraton Machines of 2015 and The Urban Field Glass Project / Visionary Sightseeing Binoculars 2008, 20013, 2021, 2022. The Public Utteraton Machines records people's opinions of other public art in New York, such as Jeff Koon's Split Rocker and displays responses online.

An outdoor interactive installation by Maurizio Bolognini (Genoa, 2005), which everybody can modify by using a cell phone.

 

Public art on display at Clarence Dock, Leeds, UK

New genre public art

In the 1990s, some artists called for artistic social intervention in public space. These efforts employed the term "new genre public art" in addition to the terms "contextual art", "relational art", "participatory art", "dialog art", "community-based art", and "activist art". "New genre public art" is defined by Suzanne Lacy as "socially engaged, interactive art for diverse audiences with connections to identity politics and social activism". Mel Chin's Fundred Dollar Bill Project is an example of an interactive, social activist public art project. Rather than metaphorically reflecting social issues, new genre public art strove to explicitly empower marginalized groups while maintaining aesthetic appeal. An example was curator Mary Jane Jacob's 1993 public art show "Culture in Action" that investigated social systems though engagement with audiences that typically did not visit traditional art museums.

Curated public art

Salifou Lindou, Face à l'eau, Bonamouti-Deido, Douala, 2010. Commissioned by doual'art for the SUD Salon Urbain de Douala.

The term "curated public art" refers to public art produced by a community or public who "commissions" a work in collaboration with a curator-mediator. An example is the doual'art project in Douala (Cameroon, 1991) that is based on a commissioning system that brings together the community, the artist and the commissioning institution for the realization of the project.

Memorial public art

Memorials for individuals, groups of people or events are sometimes represented through public art. Examples are Maya Lin's Vietnam War Memorial in Washington DC, Tim Tate's AIDS Monument in New Orleans, and Kenzō Tange's Cenotaph for the A-bomb Victims in Hiroshima Peace Memorial Park in Japan.

Controversies

Sculpture for an objective experience of architecture – David Chipperfield and Antony Gormley, Kivik Art Centre, Sweden (2008)

Public art is sometimes controversial. The following public art controversies have been notable:

• Detroit's Heidelberg Project was controversial for several decades since its inception in 1986 due to its garish appearance.
• Richard Serra's minimalist piece Tilted Arc was removed from Foley Square in New York City in 1989 after office workers complained their work routine was disrupted by the piece. A public court hearing ruled against continued display of the work.
• Victor Pasmore's Apollo Pavilion in the English New Town of Peterlee has been a focus for local politicians and other groups complaining about the governance of the town and allocation of resources. Artists and cultural leaders mounted a campaign to rehabilitate the reputation of the work with the Baltic Centre for Contemporary Art commissioning artists Jane and Louise Wilson to make a video installation about the piece in 2003.
• Sam Durant's Scaffold (2017), installed in the Walker Art Center's garden represented the gallows used in seven government hangings. Native American groups found the work offensive, as 38 Dakota people had been hung at Mankato, Minnesota. The artist agreed to dismantle and permit the tribal elders to burn and bury the piece.
• Maurice Agis' Dreamspace V, a huge inflatable maze erected in Chester-le-Street, County Durham, killed two women and seriously injured a three-year-old girl in 2006 when a strong wind broke its moorings and carried it 30 ft (9.1 m) into the air, with thirty people trapped inside.

Online documentation

Online databases of local and regional public art emerged in the 1990s and 2000s in tandem with the development of web-based data. Online public art databases can be general or selective (limited to sculptures or murals), and they can be governmental, quasi-governmental, or independent. Some online databases, such as the Smithsonian American Art Museum's Archives of American Art. It currently holds over six thousand works in its database.

There are dozens of non-government organizations and educational institutions that maintain online public art databases of public artworks covering numerous areas, including the National Endowment for the Arts, WESTAF, Public Art Fund, Creative Time, and others. Public Art Online, maintains a database of public art works, essays and case studies, with a focus on the UK. The Institute for Public Art, based in the UK, maintains information about public art on six continents.

The WikiProject Public art project began in 2009 and strove to document public art around the globe. While this project received initial attention from the academic community, it mainly relied on temporary student contributions. Its status is currently unknown.

Pro bono

From Wikipedia, the free encyclopedia

https://en.wikipedia.org/wiki/Pro_bono 

Pro bono publico (English: 'for the public good'), usually shortened to pro bono, is a Latin phrase for professional work undertaken voluntarily and without payment. In the United States, the term typically refers to provision of legal services by legal professionals for people who are unable to afford them.

Pro bono publico is also used in the United Kingdom to describe the central motivation of large organizations, such as the National Health Service and various NGOs which exist "for the public good" rather than for shareholder profit, but it equally or even more applies to the private sector where professionals like lawyers and bankers offer their specialist skills for the benefit of the community or NGOs.

Legal counsel

Pro bono legal counsel may assist an individual or group on a legal case by filing government applications or petitions. A judge may occasionally determine that the loser should compensate a winning pro bono counsel.

Philippines

Sen. Jose W. Diokno, a human rights lawyer who coined the term "developmental legal aid"

In late 1974, former Philippine Senator Jose W. Diokno was released from prison as a political detainee. He set out as a litigation lawyer to devise a means to combat the Marcos dictatorship and introduced the term "developmental legal aid", which involved lawyers providing pro bono legal services but also providing allowances to their clients, who were normally the urban poor, informal settlers, farmers, and victims of Martial law under Ferdinand Marcos. Diokno set up the Free Legal Assistance Group or FLAG, which is the oldest human rights organization in the country. During martial law FLAG has handled most of the human rights cases against the military police and the administration. Eventually the concept of developmental legal aid has grown and fresh lawyers are required to conduct part-time free legal aid for a considerable amount of time, otherwise called the Community Legal Aid Service (CLAS) Rule. Many developmental legal services are provided by most law firms and NGOs in the Philippines.

South Korea

South Korean lawyers are required to complete at least 30 hours of pro bono work per year; however, the local bar associations can reduce this requirement to 20 hours. Those who have a good reason not to fulfill the requirement may pay to a pro bono fund ₩20,000–30,000 (US$17-26) per hour instead.

United Kingdom

Since 2003, many UK law firms and law schools have celebrated an annual Pro Bono Week, which encourages solicitors and barristers to offer pro bono services and increases general awareness of pro bono service. LawWorks (the operating name for the Solicitors Pro Bono Group) is a national charity that works with solicitors and law students, encouraging and supporting them in carrying out legal pro bono work. It also acts as a clearing house for pro bono casework. Individuals and community groups may apply to the charity for free legal advice and mediation, where they could not otherwise afford to pay and are not entitled to legal aid. Advocates for International Development, which exclusively brokers international pro bono contributing towards the Sustainable Development Goals, operates from a London base. Many barristers offer pro bono services as a direct response the Legal Aid cuts brought by LASPO 2012, from which they make no profit. The Bar Council has revealed that just under a quarter of the bar offer pro bono; this is 3,486 barristers. Additionally, in 2018, the Bar contributed almost 11,000 hours of pro bono work.

United States

Lawyers in the United States are recommended under American Bar Association (ABA) ethical rules to contribute at least 50 hours of pro bono service per year. Some state bar associations, however, may recommend fewer hours. Rule 6.1 of the New York Rules of Professional Conduct strongly encourages lawyers to aspire to provide at least 50 hours of pro bono service each year and quantifies the minimal financial contributions that lawyers should aspire to make to organizations providing legal services to the poor and underserved. In contrast, other states, such as Illinois, do not have recommended hours, yet require annual disclosure of voluntary pro bono hours and contributions made to pro bono organizations.

The Chief Judge of New York has also instituted a requirement that applicants who plan to be admitted in 2015 and onward must complete 50 hours of pro bono service in order to qualify. All attorneys who register must report their voluntary pro bono hours or voluntary contributions.

The ABA has conducted four national surveys of pro bono service: one released in August 2005, the second in February 2009, the third in March 2013 and the fourth in April 2018.

The ABA Standing Committee on Pro Bono and Public Service and its project, the Center for Pro Bono, are a national source of information, resources and assistance to support, facilitate, and expand the delivery of pro bono legal help. The ABA Standing Committee also sponsors Pro Bono Week during the week of 23–29 October. The ABA Standing Committee on Legal Assistance for Military Personnel and Section of Litigation jointly sponsor the ABA Military Pro Bono Project, which delivers pro bono legal assistance to enlisted, active-duty military personnel.

In an October 2007 press conference reported in The Wall Street Journal and The New York Times, the law student group Building a Better Legal Profession released its first annual ranking of top law firms by average billable hours, pro bono participation, and demographic diversity. The report found that most large firms fall short of their pro bono targets. The group has sent the information to top law schools around the country, encouraging students to take this data into account when choosing where to work after graduation.

The American Lawyer compiles, from among its 200 top-rated law firms, those that contributed the most pro bono hours of service during the previous calendar year, publishing the list annually.

The Netherlands

In the Netherlands, legal services offered without payment are known as pro deo.

Examples within specific legal sectors

In intellectual property

To help make services related to intellectual property (IP) more accessible, a number of organizations have created pro bono initiatives. These organizations offer support from legal professionals at no cost. The services usually cover the professional fees associated with the related services, but no official fees due to a cost to intellectual property offices.

International efforts

Established in 2015, the Inventor Assistance Program helps inventors navigate the patent system in their own country and a number of other jurisdictions at no cost. Individual inventors and enterprise must be from a participating country and meet certain eligibility criteria. Applicants apply via the IAP Online Platform. Current participating countries include Colombia,  Chile, Ecuador, Morocco, Peru, the Philippines, and South Africa. The program is operated by the World Intellectual Property Organization (WIPO). In 2020, the WIPO GREEN reinstated their pro bono legal advice program.

The Inter-American Association of Intellectual Property (offers pro bono services related to intellectual property. Services include applications for copyright, patent, and trademarks, academic training, advice on IP related contracts, and IP related disputes.

The International Trademark Association matches eligible clients facing trademark issues with member attorneys who volunteer to provide services free of charge. The program initially accepted applications in the United States and Latin America and later expanded globally.

The European Union Intellectual Property Office (EUIPO) offers free personalized IP support to small businesses for EU based SMEs. The work is not limited to a specific field of IP but covers virtually all IP aspects and services, including help in filing patents, trade marks, design applications, copyright, plant varieties, geographical indications, trade secrets and domain names, as well as licensing, enforcement, franchising, tech transfer of IP rights or any “other IP matters and disputes”.

National efforts

In the United States, the Patent Pro Bono Program is a nationwide network of independently operated regional programs that matches volunteer patent professionals with financially under-resourced inventors and small businesses for the purpose of securing patent protection.

In the United Kingdom, a collaboration between local intellectual property organizations called IP Pro Bono offers intellectual property advice and legal support or claimants and defendants in intellectual property disputes.

Outside the legal sector

Corporate pro bono efforts generally focus on building the capacity of local nonprofits or mentoring local businesses. There are many models that businesses use and tailor to their specific strengths. They may loan employees, provide coaching and mentoring, complete a service marathon, create standardized team projects, engage in open-ended outsourcing, provide sector-wise solutions, perform general contracting, or work on a signature issue.

Loaned employee

In this model, companies loan a fully trained and paid-for employee to the non-profit organization. Employees apply for the coveted opportunity to pursue a pro bono interest by lending their knowledge and experience. They use their workplace skills in a hands-on or consulting role to build the non-profit's capacity.

Functional coaching and mentoring

Employees match up with their nonprofit peers, form a relationship, and share functional expertise. They may connect them with assets for growth or revise their business models. For commodities and service-based businesses, coaching and mentoring is a fresh way for them to do philanthropy. It builds a stronger market for the businesses by strengthening the local economy and cultivates important skills for the service providers and recipients.

Marathon

An event where people meet up to do pro bono work for many continuous hours.

Standardized team projects

Individuals are placed on teams, each with specific roles and responsibilities. Each project is scoped and structured around a standard deliverable based on the needs of the nonprofit partners. Team projects are meant as fun team-building activities or as highly competitive competitions to examine leadership abilities in employees.

Open-ended outsourcing

A company makes its services available to a specific number of nonprofit organizations on an ongoing, as needed basis. Volunteers act in a mentor capacity to fill a non-profit's need. Often employees use workplace skills to provide services that non-profits do not have the resources to fund.

Sector-wide solutions

A company creates a deliverable pro bono resource that can be applicable to all nonprofits across the sector. Similar to creating products for consumers, this pro bono model advocates creating products that will be distributed for free or at a greatly reduced cost. Often these are software or other tech services.

General contracting

An entity coordinates and oversees internal and external resources, promoting cross-sector collaboration to address a specific social problem. Contracting is generally done in an ad-hoc capacity and by intermediary organizations such as AMAIDI International gGmbH, Common Impact, Points of Light or Taproot Foundation.

Signature issue

Signature issues combine corporate assets with pro bono work to fight social problems. This is as much a corporate branding initiative as it is an altruistic endeavor. Pro bono volunteers that come en masse from a company become associated with that cause while combating social issues.

Forecasting

From Wikipedia, the free encyclopedia

https://en.wikipedia.org/wiki/Forecasting 

Forecasting is the process of making predictions based on past and present data. Later these can be compared (resolved) against what happens. For example, a company might estimate their revenue in the next year, then compare it against the actual results. Prediction is a similar, but more general term. Forecasting might refer to specific formal statistical methods employing time series, cross-sectional or longitudinal data, or alternatively to less formal judgmental methods or the process of prediction and resolution itself. Usage can differ between areas of application: for example, in hydrology the terms "forecast" and "forecasting" are sometimes reserved for estimates of values at certain specific future times, while the term "prediction" is used for more general estimates, such as the number of times floods will occur over a long period.

Risk and uncertainty are central to forecasting and prediction; it is generally considered good practice to indicate the degree of uncertainty attaching to forecasts. In any case, the data must be up to date in order for the forecast to be as accurate as possible. In some cases the data used to predict the variable of interest is itself forecast.

Applications

Forecasting has applications in a wide range of fields where estimates of future conditions are useful. Depending on the field, accuracy varies significantly. If the factors that relate to what is being forecast are known and well understood and there is a significant amount of data that can be used, it is likely the final value will be close to the forecast. If this is not the case or if the actual outcome is affected by the forecasts, the reliability of the forecasts can be significantly lower.

Climate change and increasing energy prices have led to the use of Egain Forecasting for buildings. This attempts to reduce the energy needed to heat the building, thus reducing the emission of greenhouse gases. Forecasting is used in customer demand planning in everyday business for manufacturing and distribution companies.

While the veracity of predictions for actual stock returns are disputed through reference to the Efficient-market hypothesis, forecasting of broad economic trends is common. Such analysis is provided by both non-profit groups as well as by for-profit private institutions.

Forecasting foreign exchange movements is typically achieved through a combination of chart and fundamental analysis. An essential difference between chart analysis and fundamental economic analysis is that chartists study only the price action of a market, whereas fundamentalists attempt to look to the reasons behind the action. Financial institutions assimilate the evidence provided by their fundamental and chartist researchers into one note to provide a final projection on the currency in question.

Forecasting has also been used to predict the development of conflict situations. Forecasters perform research that uses empirical results to gauge the effectiveness of certain forecasting models. However research has shown that there is little difference between the accuracy of the forecasts of experts knowledgeable in the conflict situation and those by individuals who knew much less.

Similarly, experts in some studies argue that role thinking does not contribute to the accuracy of the forecast. The discipline of demand planning, also sometimes referred to as supply chain forecasting, embraces both statistical forecasting and a consensus process. An important, albeit often ignored aspect of forecasting, is the relationship it holds with planning. Forecasting can be described as predicting what the future will look like, whereas planning predicts what the future should look like. There is no single right forecasting method to use. Selection of a method should be based on your objectives and your conditions (data etc.). A good place to find a method, is by visiting a selection tree. An example of a selection tree can be found here. Forecasting has application in many situations:

• Supply chain management - Forecasting can be used in supply chain management to ensure that the right product is at the right place at the right time. Accurate forecasting will help retailers reduce excess inventory and thus increase profit margin. Studies have shown that extrapolations are the least accurate, while company earnings forecasts are the most reliable. Accurate forecasting will also help them meet consumer demand.
• Customer demand planning
• Economic forecasting
• Earthquake prediction
• Egain forecasting
• Energy forecasting for renewable power integration
• Finance against risk of default via credit ratings and credit scores
• Land use forecasting
• Player and team performance in sports
• Political forecasting
• Product forecasting
• Sales forecasting
• Technology forecasting
• Telecommunications forecasting
• Transport planning and Transportation forecasting
• Weather forecasting, Flood forecasting and Meteorology

Forecasting as training, Betting and Futarchy

In several cases, the forecast is either more or less than a prediction of the future.

In Philip E. Tetlock's Superforecasting, he discusses forecasting as a method of improving ones ability to make decisions. A person can become better calibrated - ie having things they give 10% credence to happening 10% of the time. Or they can forecast things more confidently - coming to the same conclusion but earlier. Some have claimed that that forecasting is a transferrable skill with benefits to other areas of discussion and decision making.

Betting on sports or politics is another form of forecasting. Rather than being used as advice, bettors are paid based on if they predicted correctly. While decisions might be made based on these bets (forecasts), the main motivation is generally financial.

Finally, Futarchy is a form of government where forecasts of the impact of government action are used to decide which actions are taken. Rather than advice, in Futarchy's strongest form, the action with the best forecasted result is automatically taken.

Categories of forecasting methods

Qualitative vs. quantitative methods

Qualitative forecasting techniques are subjective, based on the opinion and judgment of consumers and experts; they are appropriate when past data are not available. They are usually applied to intermediate- or long-range decisions. Examples of qualitative forecasting methods are informed opinion and judgment, the Delphi method, market research, and historical life-cycle analogy.

Quantitative forecasting models are used to forecast future data as a function of past data. They are appropriate to use when past numerical data is available and when it is reasonable to assume that some of the patterns in the data are expected to continue into the future. These methods are usually applied to short- or intermediate-range decisions. Examples of quantitative forecasting methods are last period demand, simple and weighted N-Period moving averages, simple exponential smoothing, poisson process model based forecasting and multiplicative seasonal indexes. Previous research shows that different methods may lead to different level of forecasting accuracy. For example, GMDH neural network was found to have better forecasting performance than the classical forecasting algorithms such as Single Exponential Smooth, Double Exponential Smooth, ARIMA and back-propagation neural network.

Average approach

In this approach, the predictions of all future values are equal to the mean of the past data. This approach can be used with any sort of data where past data is available. In time series notation:

${\displaystyle {\hat{y}}_{T+h|T}=\overline{y}=(y_1+...+y_T)/T}$ 

where ${\displaystyle y_1,...,y_T}$ is the past data.

Although the time series notation has been used here, the average approach can also be used for cross-sectional data (when we are predicting unobserved values; values that are not included in the data set). Then, the prediction for unobserved values is the average of the observed values.

Naïve approach

Naïve forecasts are the most cost-effective forecasting model, and provide a benchmark against which more sophisticated models can be compared. This forecasting method is only suitable for time series data. Using the naïve approach, forecasts are produced that are equal to the last observed value. This method works quite well for economic and financial time series, which often have patterns that are difficult to reliably and accurately predict. If the time series is believed to have seasonality, the seasonal naïve approach may be more appropriate where the forecasts are equal to the value from last season. In time series notation:

${\displaystyle {\hat{y}}_{T+h|T}=y_T}$

Drift method

A variation on the naïve method is to allow the forecasts to increase or decrease over time, where the amount of change over time (called the drift) is set to be the average change seen in the historical data. So the forecast for time ${\displaystyle T+h}$ is given by

${\displaystyle {\hat{y}}_{T+h|T}=y_T+\frac{h}{T-1}\sum _{t=2}^T(y_t-y_{t-1})=y_T+h\left(\frac{y_T-y_1}{T-1}\right).}$ 

This is equivalent to drawing a line between the first and last observation, and extrapolating it into the future.

Seasonal naïve approach

The seasonal naïve method accounts for seasonality by setting each prediction to be equal to the last observed value of the same season. For example, the prediction value for all subsequent months of April will be equal to the previous value observed for April. The forecast for time ${\displaystyle T+h}$ is

${\displaystyle {\hat{y}}_{T+h|T}=y_{T+h-m(k+1)}}$

where ${\displaystyle m}$=seasonal period and ${\displaystyle k}$ is the smallest integer greater than ${\displaystyle (h-1)/m}$.

The seasonal naïve method is particularly useful for data that has a very high level of seasonality.

Time series methods

Time series methods use historical data as the basis of estimating future outcomes. They are based on the assumption that past demand history is a good indicator of future demand.

• Moving average
• Weighted moving average
• Exponential smoothing
• Autoregressive moving average (ARMA) (forecasts depend on past values of the variable being forecast and on past prediction errors)
• Autoregressive integrated moving average (ARIMA) (ARMA on the period-to-period change in the forecast variable)

e.g. Box–Jenkins

Seasonal ARIMA or SARIMA or ARIMARCH,

• Extrapolation
• Linear prediction
• Trend estimation (predicting the variable as a linear or polynomial function of time)
• Growth curve (statistics)
• Recurrent neural network

Relational methods

Some forecasting methods try to identify the underlying factors that might influence the variable that is being forecast. For example, including information about climate patterns might improve the ability of a model to predict umbrella sales. Forecasting models often take account of regular seasonal variations. In addition to climate, such variations can also be due to holidays and customs: for example, one might predict that sales of college football apparel will be higher during the football season than during the off season.

Several informal methods used in causal forecasting do not rely solely on the output of mathematical algorithms, but instead use the judgment of the forecaster. Some forecasts take account of past relationships between variables: if one variable has, for example, been approximately linearly related to another for a long period of time, it may be appropriate to extrapolate such a relationship into the future, without necessarily understanding the reasons for the relationship.

Causal methods include:

• Regression analysis includes a large group of methods for predicting future values of a variable using information about other variables. These methods include both parametric (linear or non-linear) and non-parametric techniques.
• Autoregressive moving average with exogenous inputs (ARMAX)

Quantitative forecasting models are often judged against each other by comparing their in-sample or out-of-sample mean square error, although some researchers have advised against this. Different forecasting approaches have different levels of accuracy. For example, it was found in one context that GMDH has higher forecasting accuracy than traditional ARIMA.

Judgmental methods

Judgmental forecasting methods incorporate intuitive judgement, opinions and subjective probability estimates. Judgmental forecasting is used in cases where there is lack of historical data or during completely new and unique market conditions.

Judgmental methods include:

• Composite forecasts
• Cooke's method
• Delphi method
• Forecast by analogy
• Scenario building
• Statistical surveys
• Technology forecasting

Artificial intelligence methods

• Artificial neural networks
• Group method of data handling
• Support vector machines

Often these are done today by specialized programs loosely labeled

• Data mining
• Machine learning
• Pattern recognition

Geometric Extrapolation with error prediction

Can be created with 3 points of a sequence and the "moment" or "index", this type of extrapolation have 100 % accuracy in predictions in a big percentage of known series database (OEIS). 

Other methods

• Granger causality
• Simulation
• Prediction market
• Probabilistic forecasting and Ensemble forecasting

Forecasting accuracy

The forecast error (also known as a residual) is the difference between the actual value and the forecast value for the corresponding period:

${\displaystyle E_t=Y_t-F_t}$

where E is the forecast error at period t, Y is the actual value at period t, and F is the forecast for period t.

A good forecasting method will yield residuals that are uncorrelated. If there are correlations between residual values, then there is information left in the residuals which should be used in computing forecasts. This can be accomplished by computing the expected value of a residual as a function of the known past residuals, and adjusting the forecast by the amount by which this expected value differs from zero.

A good forecasting method will also have zero mean. If the residuals have a mean other than zero, then the forecasts are biased and can be improved by adjusting the forecasting technique by an additive constant that equals the mean of the unadjusted residuals.

Measures of aggregate error:

Scaled-dependent errors

The forecast error, E, is on the same scale as the data, as such, these accuracy measures are scale-dependent and cannot be used to make comparisons between series on different scales.

Mean absolute error (MAE) or mean absolute deviation (MAD): ${\displaystyle MAE=MAD=\frac{\sum _{t=1}^N|E_t|}{N}}$

Mean squared error (MSE) or mean squared prediction error (MSPE): ${\displaystyle MSE=MSPE=\frac{\sum _{t=1}^N{E}_t^2}{N}}$

Root mean squared error (RMSE): ${\displaystyle RMSE=\sqrt{\frac{\sum _{t=1}^N{E}_t^2}{N}}}$

Average of Errors (E): ${\displaystyle \overline{E}=\frac{\sum _{i=1}^N{E}_i}{N}}$

Percentage errors

These are more frequently used to compare forecast performance between different data sets because they are scale-independent. However, they have the disadvantage of being extremely large or undefined if Y is close to or equal to zero.

Mean absolute percentage error (MAPE): ${\displaystyle MAPE=100\ast \frac{\sum _{t=1}^N|\frac{E_t}{Y_t}|}{N}}$

Mean absolute percentage deviation (MAPD): ${\displaystyle MAPD=\frac{\sum _{t=1}^N|E_t|}{\sum _{t=1}^N|Y_t|}}$

Scaled errors

Hyndman and Koehler (2006) proposed using scaled errors as an alternative to percentage errors.

Mean absolute scaled error (MASE): ${\displaystyle MASE=\frac{\sum _{t=1}^N|\frac{E_t}{\frac{1}{N-m}\sum _{t=m+1}^N|Y_t-Y_{t-m}|}|}{N}}$

where m=seasonal period or 1 if non-seasonal

Other measures

Forecast skill (SS): ${\displaystyle SS=1-\frac{MS{E}_{forecast}}{MS{E}_{ref}}}$

Business forecasters and practitioners sometimes use different terminology. They refer to the PMAD as the MAPE, although they compute this as a volume weighted MAPE. For more information see Calculating demand forecast accuracy.

When comparing the accuracy of different forecasting methods on a specific data set, the measures of aggregate error are compared with each other and the method that yields the lowest error is preferred.

Training and test sets

When evaluating the quality of forecasts, it is invalid to look at how well a model fits the historical data; the accuracy of forecasts can only be determined by considering how well a model performs on new data that were not used when fitting the model. When choosing models, it is common to use a portion of the available data for fitting, and use the rest of the data for testing the model, as was done in the above examples.

Cross-validation

Cross-validation is a more sophisticated version of training a test set.

For cross-sectional data, one approach to cross-validation works as follows:

1. Select observation i for the test set, and use the remaining observations in the training set. Compute the error on the test observation.
2. Repeat the above step for i = 1,2,..., N where N is the total number of observations.
3. Compute the forecast accuracy measures based on the errors obtained.

This makes efficient use of the available data, as only one observation is omitted at each step

For time series data, the training set can only include observations prior to the test set. Therefore, no future observations can be used in constructing the forecast. Suppose k observations are needed to produce a reliable forecast; then the process works as follows:

1. Starting with i=1, select the observation k + i for the test set, and use the observations at times 1, 2, ..., k+i–1 to estimate the forecasting model. Compute the error on the forecast for k+i.
2. Repeat the above step for i = 2,...,T–k where T is the total number of observations.
3. Compute the forecast accuracy over all errors.

This procedure is sometimes known as a "rolling forecasting origin" because the "origin" (k+i -1) at which the forecast is based rolls forward in time. Further, two-step-ahead or in general p-step-ahead forecasts can be computed by first forecasting the value immediately after the training set, then using this value with the training set values to forecast two periods ahead, etc.

See also

• Calculating demand forecast accuracy
• Consensus forecasts
• Forecast error
• Predictability
• Prediction intervals, similar to confidence intervals
• Reference class forecasting

Seasonality and cyclic behaviour

Seasonality

Main article: Seasonality

Seasonality is a characteristic of a time series in which the data experiences regular and predictable changes which recur every calendar year. Any predictable change or pattern in a time series that recurs or repeats over a one-year period can be said to be seasonal. It is common in many situations – such as grocery store or even in a Medical Examiner's office—that the demand depends on the day of the week. In such situations, the forecasting procedure calculates the seasonal index of the “season” – seven seasons, one for each day – which is the ratio of the average demand of that season (which is calculated by Moving Average or Exponential Smoothing using historical data corresponding only to that season) to the average demand across all seasons. An index higher than 1 indicates that demand is higher than average; an index less than 1 indicates that the demand is less than the average.

Cyclic behaviour

The cyclic behaviour of data takes place when there are regular fluctuations in the data which usually last for an interval of at least two years, and when the length of the current cycle cannot be predetermined. Cyclic behavior is not to be confused with seasonal behavior. Seasonal fluctuations follow a consistent pattern each year so the period is always known. As an example, during the Christmas period, inventories of stores tend to increase in order to prepare for Christmas shoppers. As an example of cyclic behaviour, the population of a particular natural ecosystem will exhibit cyclic behaviour when the population decreases as its natural food source decreases, and once the population is low, the food source will recover and the population will start to increase again. Cyclic data cannot be accounted for using ordinary seasonal adjustment since it is not of fixed period.

Limitations

Limitations pose barriers beyond which forecasting methods cannot reliably predict. There are many events and values that cannot be forecast reliably. Events such as the roll of a die or the results of the lottery cannot be forecast because they are random events and there is no significant relationship in the data. When the factors that lead to what is being forecast are not known or well understood such as in stock and foreign exchange markets forecasts are often inaccurate or wrong as there is not enough data about everything that affects these markets for the forecasts to be reliable, in addition the outcomes of the forecasts of these markets change the behavior of those involved in the market further reducing forecast accuracy.

The concept of "self-destructing predictions" concerns the way in which some predictions can undermine themselves by influencing social behavior. This is because "predictors are part of the social context about which they are trying to make a prediction and may influence that context in the process". For example, a forecast that a large percentage of a population will become HIV infected based on existing trends may cause more people to avoid risky behavior and thus reduce the HIV infection rate, invalidating the forecast (which might have remained correct if it had not been publicly known). Or, a prediction that cybersecurity will become a major issue may cause organizations to implement more security cybersecurity measures, thus limiting the issue.

Performance limits of fluid dynamics equations

As proposed by Edward Lorenz in 1963, long range weather forecasts, those made at a range of two weeks or more, are impossible to definitively predict the state of the atmosphere, owing to the chaotic nature of the fluid dynamics equations involved. Extremely small errors in the initial input, such as temperatures and winds, within numerical models double every five days.