It has been suggested that this article be split into articles entitled Path dependence (physics) and Path dependence (systems), accessible from a disambiguation page. (Discuss)

Path-dependence is a phrase used to mean one of two things (Pierson 2004). Some authors use path-dependence to mean simply "history matters" - a broad conception - while others use it to mean that institutions are self reinforcing - a narrow conception. It is this narrow conception which has the most explanatory force and of which the discussions below are examples. The "history matters" claim is trivially true and reduces simply to "everything has causes". Image File history File links Derived from public domain images featured at: http://commons. ...

Consider as an example the technological development of videocassette recorders (VCRs) for home use. It is argued that management errors and minor design choices by Sony led to its Betamax format being defeated in market competition by VHS in the 1980s. Two mechanisms can explain why the small but early lead gained by VHS became larger over time. The first is the bandwagon effect of VCR manufacturers in favor of the VHS format in the U.S. and Europe, who switched because they expected VHS to win the standards battle. The second was a network effect: videocassette rental stores observed that more people had VHS players and stocked up on VHS tapes; this in turn led other people to buy VHS players, and so on until there was complete vendor lock-in to VHS. An alternative explanation, of course, is that VHS was better adapted to market demands (in particular to the demand for longer cassettes for recording sports games) and that path dependence had little or nothing to do with its success. There is also some support for this latter claim. The video cassette recorder (or VCR, less popularly video tape recorder) is a type of video tape recorder that uses removable cassettes containing magnetic tape to record audio and video from a television broadcast so it can be played back later. ... Sony Corporation ) is a Japanese multinational corporation and one of the worlds largest media conglomerates with revenue of $66. ... Sonys Betamax is the 12. ... Bottom view of VHS cassette with magnetic tape exposed Top view of VHS cassette with front casing removed The Video Home System, better known by its abbreviation VHS, is a recording and playing standard. ... The bandwagon effect is the observation that people often do (or believe) things because many other people do (or believe) the same. ... A network effect is a characteristic that causes a good or service to have a value to a potential customer which depends on the number of other customers who own the good or are users of the service. ... In economics, vendor lock-in, also known as proprietary lock-in, customer lock-in, lock-in is where a customer is dependent on a vendor for products and services and cannot move to another vendor without substantial switching costs, real and/or perceived. ...

Positive feedback mechanisms like bandwagon and network effects are at the origin of path-dependence. They lead to a reinforcing pattern, in which industries 'tip' towards one or another product design. Uncoordinated standardisation can be observed in many other situations. Positive feedback is a feedback system in which the system responds to the perturbation in the same direction as the perturbation (It is sometimes referred to as cumulative causation). ... Standardisation or standardization (sometimes abbreviated s13n), in the context related to technologies and industries, is the process of establishing a technical standard among competing entities in a market, where this will bring benefits without hurting competition. ...

Examples from economics, history, software, and biology are presented below.

Economics

Path dependency theory was originally developed by economists to explain technology adoption processes and industry evolution. The theoretical ideas have had a strong influence on evolutionary economics (e.g., Nelson & Winter 1982). Evolutionary economics is a relatively new economic methodology that is modeled on biology. ...

There are many models and empirical cases where economic processes do not progress steadily toward some pre-determined and unique equilibrium, so that the nature of any equilibrium achieved depends partly on the process of getting there. The outcome of a path dependent process will often not converge towards a unique equilibrium but instead reach one of several equilibria (sometimes known as absorbing states). Economics (deriving from the Greek words οίκω [okos], house, and νέμω [nemo], rules hence household management) is the social science that studies the allocation of scarce resources to satisfy unlimited wants. ... Price of market balance In economics, economic equilibrium is simply a state of the world where economic forces are balanced and in the abscence of external shocks the (equilibrium) values of economic variables will not change. ... In the absence of a more specific context, convergence denotes the approach toward a definite value, as time goes on; or to a definite point, a common view or opinion, or toward a fixed or equilibrium state. ...

This dynamic vision of economic evolution is very different from the neo-classical economics tradition, which in its simplest form assumed that only a single outcome could possibly be reached, regardless of initial conditions or transitory events. With path dependence, both the starting point and 'accidental' events (noise) can have significant effects on the ultimate outcome. In each of the following examples it is possible to identify some random events that disrupted the ongoing course, with irreversible consequences: Neoclassical economics is the grouping of a number of schools of thought in economics. ... This article is about noise as in sound. ... Random redirects here. ...

• In the 1980s, the U.S. dollar exchange rate appreciated, lowering the world price of tradable goods below the cost of production in many (previously successful) U.S. manufactures. Some of the factories which closed as a result could now be run at a (cash-flow) profit, because the dollar has declined. However, re-opening them is too expensive. This is an example of hysteresis and irreversiblity.

• In economic development, it is said (initially by Paul David in 1985) that a standard which is first-to-market can become entrenched (like the QWERTY layout in typewriters still used in computer keyboards). He called this "path dependence", and argued that inferior standards can persist simply because of the legacy they have built up. The case against QWERTY has been criticized (e.g. by The Fable of the Keys), but standards are clearly very important in modern economies, and the significance of path dependence in determining how they form is the subject of economic debate.

• Economists since Adam Smith have noted that businesses of a certain type tend to congregate geographically, attracting workers with skills in that business, which draw in more businesses looking for employees with experience. There may not have been any particular reason to prefer one place to another before the industry developed, but as it has become concentrated in one place any new entrants elsewhere are at a disadvantage, and will tend to move into the hub if possible, further increasing its relative efficiency. The mechanism at work is a network effect. New Trade Theory and Krugman's "New Economic Geography" are based partly on this story.

• If the economy follows adaptive expectations, future inflation is partly determined by past experience with inflation, since experience determines expected inflation and this is a major determinant of realized inflation.

• A transitory high rate of unemployment during a recession can lead to a permanently higher unemployment rate because of the skills loss (or skill obsolescence) by the unemployed along with a deterioration of work attitudes. In other words, cyclical unemployment may generate structural unemployment. The negative effects get reinforced by potential employers' negative view of the capacities of job-seekers who have been out of a job for a long time. This structural hysteresis model of the labour market differs from the prediction of a "natural" unemployment rate or NAIRU, around which 'cyclical' unemployment is said to move randomly. Since structural unemployment is endogenous, the NAIRU is also endogenous (see the article by Hargreaves Heap cited below).

Liebowitz and Margolis distinguish between different types of path dependence. Some types of path dependence do not imply inefficiencies and, while they may be interesting to study for other reasons, do not challenge the policy implications of neoclassical economics. Only what they call "third degree" path dependence - for example, a situation where society would be better off if everybody switched standards simultaneously, but they do not do so because there is no central authority to force them to, and they cannot all coordinate - involves such a challenge. They argue that such situations can be expected to be rare for theoretical reasons and that this prediction is borne out by what they consider the unconvincing examples typically discussed in this context (mainly VHS vs. Beta and QWERTY vs. Dvorak). A tradable good or service can be sold in another location distant from where it was produced. ... Motto: (Out Of Many, One) (traditional) In God We Trust (1956 to date) Anthem: The Star-Spangled Banner Capital Washington D.C. Largest city New York City None at federal level (English de facto) Government Federal constitutional republic  - President George Walker Bush (R)  - Vice President Dick Cheney (R) Independence from... Hysteresis is a property of systems (usually physical systems) that do not instantly follow the forces applied to them, but react slowly, or do not return completely to their original state: that is, systems whose states depend on their immediate history. ... For the song by Linkin Park, see QWERTY (song). ... For the song by Linkin Park, see QWERTY (song). ... For other persons named Adam Smith, see Adam Smith (disambiguation). ... A network effect is a characteristic that causes a good or service to have a value to a potential customer which depends on the number of other customers who own the good or are users of the service. ... This article does not cite any references or sources. ... In economics, adaptive expectations means that people base their expectations of what will happen in the future based on what has happened in the past. ... Realization, in the accounting (US GAAP) context, has a broader meaning than in the general economic context, in that changes in the market price of marketable securities held for trading (speculative) reasons are considered realized at the end of each accounting period even if the reporting entity continues to hold... This article does not cite any references or sources. ... In macroeconomics, the definition of recession is a decline in any countrys Gross Domestic Product (GDP), or negative real economic growth, for two or more successive quarters of a year. ... Labour economics seeks to understand the functioning of the market for labour. ... The term NAIRU is an acronym for Non-Accelerating Inflation Rate of Unemployment. ... Look up Endogenous in Wiktionary, the free dictionary. ...

In technical terms, a path-dependence (stochastic system) can be defined as "one possessing an asymptotic distribution that evolves as a consequence (function of) the process's own history". This is also known as a "non-ergodic stochastic process". Confusingly, the use of "path dependent" to describe labour market hysteresis has the opposite sense to the term's meaning in the adaptive expectations model of inflation. In labour market economics, some "path dependent" models have unemployment following a driftless random walk, based solely on its previous level (a Markov process). For other uses, see ergodic (disambiguation). ... In the mathematics of probability, a stochastic process is a random function. ... In economics, adaptive expectations means that people base their expectations of what will happen in the future based on what has happened in the past. ... It has been suggested that this article or section be merged with Markov property. ...

History and the social sciences

See also: historical institutionalism

The history of humanity is almost by definition path-dependent. Accidental events such as the death at an early age of major historical figures like Napoleon or Hitler would likely have altered the political geography of Europe and even the languages spoken in different countries today. Historical institutionalism (HI) is a social science method of inquiry that uses institutions as subject of study in order to find, measure and trace patterns and sequences of social, political, economic behavior and change accross time and space. ... For other uses, see Napoleon (disambiguation). ... Adolf Hitler Adolf Hitler (April 20, 1889 – April 30, 1945, standard German pronunciation in the IPA) was the Führer (leader) of the National Socialist German Workers Party (Nazi Party) and of Nazi Germany from 1933 to 1945. ...

Recent methodological work in comparative politics and sociology has adapted the concept of path dependence into analyses of political and social phenomenon. Path dependence has primarily been used in comparative-historical analyses to analyze the development and persistence of institutions, whether they be social, political, or cultural. There are arguably two discernable types of path-dependent processes: The comparative method (in linguistics) is a method used to detect genetic relationships between languages and to establish a consistent relationship hypothesis by reconstructing: the common ancestor of the languages in question, a plausible sequence of regular changes by which the historically known languages can be derived from that common... An institution is a group, tenet, maxim, or organization created by a group of humans. ...

• One is the "critical juncture" framework, most notably utilized by Ruth and David Collier in political science. In the critical juncture framework, antecedent conditions define and delimit agency during a critical juncture in which actors make contingent choices that set a specific trajectory of institutional development and consolidation that is difficult to reverse. This is akin to the concepts of vendor lock-in or positive feedback derived from path dependence in economics.

The critical juncture framework has been used to explain the development and persistence of welfare states, labor incorporation in Latin America, and the variations in economic development between countries, among other things. The Politics series Politics Portal This box:      Political Science is the field concerning the theory and practice of politics and the description and analysis of political systems and political behaviour. ... Modal logic, or (less commonly) intensional logic is the branch of logic that deals with sentences that are qualified by modalities such as can, could, might, may, must, possibly, and necessarily, and others. ... An institution is a group, tenet, maxim, or organization created by a group of humans. ... In economics, vendor lock-in, also known as proprietary lock-in, customer lock-in, lock-in is where a customer is dependent on a vendor for products and services and cannot move to another vendor without substantial switching costs, real and/or perceived. ... Positive feedback is a feedback system in which the system responds to the perturbation in the same direction as the perturbation (It is sometimes referred to as cumulative causation). ... There are three main interpretations of the idea of a welfare state: the provision of welfare services by the state. ... Latin America consists of the countries of South America and some of North America (including Central America and some the islands of the Caribbean) whose inhabitants mostly speak Romance languages, although Native American languages are also spoken. ... Economic development is the development of economic wealth of countries or regions for the well-being of their inhabitants. ...

An influential attempt to give some formal rigor to thinking about path dependence in political science is notably that of Paul Pierson. Pierson draws in part on ideas from economics (see above). His efforts in this regard have been questioned by Herman Schwartz, who argues that forces analogous to those identified in the economic literature are not pervasive in the political realm, where larger forces and the strategic exercise of power give rise to, maintain, and transform institutions.

In a related vein, scholars such as Kathleen Thelen caution that the historical determinism in path-dependent frameworks ignore the constant renegotiation of institutional configurations. She suggests that institutions undergo moments of institutional evolution wherein key actors renegotiate the configuration and purpose of institutions. Determinism is the philosophical proposition that every event, including human cognition and behavior, decision and action, is causally determined by an unbroken chain of prior occurrences. ...

• The other path-dependent process deals with "reactive sequences" where a primary event sets off a temporally-linked and causally-tight chain of events that is nearly uninterruptible. These reactive sequences have been used to link the death of Martin Luther King, Jr. with welfare expansion and the industrial revolution in England with the development of the steam engine.

Martin Luther King redirects here. ... A Watt steam engine, the steam engine that propelled the Industrial Revolution in Britain and the world. ... For other uses, see England (disambiguation). ... // The term steam engine may also refer to an entire railroad steam locomotive. ...

Typography

Path dependence also influences the progression of language, grammar and typographical conventions. For example, in the contrast between American and British English, there are different grammatical rules for the placement of punctuation relative to quotation marks in a sentence.

For example, compare the following:

 There are 720 permutations of the sequence "1, 2, 3, 4, 5, 6". (U.K. but not U.S.) There are 720 permutations of the sequence "1, 2, 3, 4, 5, 6." (U.S. but not U.K.) 

This difference has been attributed to path dependence. Historically, when print was handset, American printers found it expedient to always place the period inside quotation marks, even when not logically consistent with the text, because this made it easier to prevent accidental displacement of the period. Even though the technical justifications for this convention no longer apply, the grammatical rule has persisted.^[1]

Technology

In the computer and software markets, legacy systems indicate path dependence: customers' needs in the present market often include the ability to read data or run programs from past generations of products. Thus, for instance, a customer may need not merely the best available word processor but rather the best available word processor that can read Microsoft Word files. Such limitations in compatibility contribute to lock-in, and more subtly, to design compromises for independently developed products if they attempt to be compatible. It is not clear, however, that there is any inefficiency involved in the costs of remaining compatible with past decisions. This article is about the machine. ... Computer software (or simply software) refers to one or more computer programs and data held in the storage of a computer for some purpose. ... It has been suggested that Legacy code be merged into this article or section. ... A word processor (also more formally known as a document preparation system) is a computer application used for the production (including composition, editing, formatting, and possibly printing) of any sort of viewable or printed material. ... Microsoft Word is Microsofts flagship word processing software. ... The term compatibility has the following meanings: In telecommunication, the capability of two or more items or components of equipment or material to exist or function in the same system or environment without mutual interference. ...

Biological evolution

Evolution is considered by some to be path-dependent: random mutations occurring in the past have had long-term effects on current life forms, some of which may no longer be adaptive to current conditions. For instance, there is a controversy about whether the panda's thumb is a leftover trait or not. This article is about evolution in biology. ...

Physics

The process of Spontaneous symmetry breaking in physics is very similar to path dependence. For example, in materials that exhibit Ferromagnetism, magnetic domains form in otherwise completely homogeneous materials. Spontaneous symmetry breaking in physics takes place when a system that is symmetric with respect to some symmetry group goes into a vacuum state that is not symmetric. ... Ferromagnetism is the phenomenon by which materials, such as iron, in an external magnetic field become magnetized and remain magnetized for a period after the material is no longer in the field. ...

Notes

1. ^ (see e.g., http://grammar.ccc.commnet.edu/grammar/marks/quotation.htm#footnote, http://www.grammartips.homestead.com/inside.html, Quotation_mark#Typographical_considerations

Quotation marks or inverted commas (also called quotes and speech marks) are punctuation marks used in pairs to set off speech, a quotation, a phrase or a word. ...

References

• Arrow, Kenneth J. (1963), 2nd ed. Social Choice and Individual Values. Yale University Press, New Haven, pp. 119-120 (constitutional transitivity as alternative to path dependence on the status quo).
• Arthur, W. Brian (1994), Increasing Returns and Path Dependence in the Economy, Ann Arbor, Michigan: University of Michigan Press.
• Boas, Taylor C. (2007), "Conceptualizing Continuity and Change: The Composite-Standard Model of Path Dependence", Journal of Theoretical Politics 19(1): 33-54.
• David, Paul A. (2000), "Path dependence, its critics and the quest for ‘historical economics’", in P. Garrouste and S. Ioannides (eds), Evolution and Path Dependence in Economic Ideas: Past and Present, Edward Elgar Publishing, Cheltenham, England.
• Liebowitz, S.J. and Stephen E. Margolis (1990), "The Fable of the Keys", Journal of Law & Economics vol. XXXIII (April 1990)
• Mahoney, James (2000), “Path Dependence in Historical Sociology,” Theory and Society 29:4, pp. 507-548.
• Stephen E. Margolis and S.J. Liebowitz (2000), "Path Dependence, Lock-In, and History"
• Nelson, R. & S. Winter (1982), An evolutionary theory of economic change. Harvard University Press.
• Pierson, Paul (2000). "Increasing Returns, Path Dependence, and the Study of Politics." American Political Science Review, June.
• _____ (2004), "Politics in Time"
• Puffert, Douglas J. (1999), ["Path Dependence in Economic History"] (based on the entry “Pfadabhängigkeit in der Wirtschaftsgeschichte,” in the Handbuch zur evolutorischen Ökonomik)
• _____ (2001), "Path Dependence in Spatial Networks: The Standardization of Railway Track Gauge"
• Schwartz, Herman. "Down the Wrong Path: Path Dependence, Increasing Returns, and Historical Institutionalism." http://www.people.virginia.edu/~hms2f/Path.pdf

Kenneth Arrows monograph Social Choice and Individual Values (1951, 2nd ed. ...

External links

• Article on Path Dependence from EH.NET's Encyclopedia
• "QWERTY, Lock-in, and Path Dependence" Web page that argues that lock-in leads to market failure and provides a list of references although it short shrifts articles from those on the other side.
• Shawn Hargreaves Heap (1980), "Choosing the Wrong 'Natural' Rate: Accelerating Inflation or Decelerating Employment and Growth?" Economic Journal 90(359) (Sept): 611-20 (ISSN 0013-0133) develops the idea that persistently high unemployment can cause the "natural" rate of unemployment to rise.
• "Doctoral Program Research on Organizational Paths" Web page form the Freie Universitaet Berlin Faculty of Business Administration and Economic.
• "Our Love Of Sewers: A Lesson in Path Dependence"