A de facto standard is a custom or convention that has achieved a dominant position by public acceptance or market forces (for example, by early entrance to the market). De facto is a Latin phrase that means in fact (literally by or from fact) in the sense of "in practice but not necessarily ordained by law" or "in practice or actuality, but not officially established", as opposed to de jure.
The term de facto standard is used in contrast with obligatory standards (also known as "de jure standards"); or to express the dominant voluntary standard, when there is more than one standard available for the same use.
In social sciences, a voluntary standard that is also a de facto standard is a typical solution to a coordination problem.[1] The choice of a de facto standard tends to be stable in situations in which all parties can realize mutual gains, but only by making mutually consistent decisions. In contrast, an enforced "de jure standard" is a solution to the prisoner's problem.
A selection of well-known and illustrative examples of de facto and de jure standards are:
with consolidation by tradition of use:
The driver's seat side in a given country starts as a user/industry preference, turning to a local tradition, then a traffic code local norm.
The QWERTY system was one of several options for the layout of letters on typewriter (and later keyboard) keys. It was developed to prevent adjacent keys from jamming on early and later mechanical typewriters, often attributed to the typist's speed.[2] It became a de facto standard because it was used on the most commercially successful early typewriters and is now used on devices which have no moving parts such as touchscreens.
The MP3 audio format started as an alternative to WAV for Internet music distribution, then replaced it — it is now supported by the vast majority of music players, audio transport, audio storage and noncommercial media. WAV and MP3 are also "de jure ISO formats".
with consolidation by uniqueness and efficiency:
HTML (computer file format) started as "de facto" (1993-1995) and became the "de jure" standard (1995–present day).
PDF (computer file format) was first created in 1993 by Adobe. Adobe internal standards were part of its software quality systems, but they were neither published nor coordinated by a standards body. With the Acrobat Reader program available for free, and continued support of the format, PDF eventually became the de facto standard for printable documents. In 2005, PDF/A became a de jure standard as ISO 19005-1:2005.[3] In 2008 Adobe's PDF 1.7 became ISO 32000-1:2008