Not Invented Here (NIH) is a term used to describe persistent social, corporate or institutional culture that avoids using or buying already existing products, research or knowledge because of its different origins. It is normally used in a pejorative sense, and may be considered an antipattern. The opposite culture is sometimes denoted Proudly Found Elsewhere (PFE).
As a social phenomenon, "Not Invented Here" syndrome is manifested as an unwillingness to adopt an idea or product because it originates from another culture, a form of nationalism.
An example is the low acceptance of early British-made home computers in Japan and the USA and Japanese-made ones in Britain and the USA. For example the Timex Sinclair 2068 received almost no attention in the USA, while its Sinclair Spectrum predecessor became hugely successful in Britain and the rest of Europe. Similarly the Japanese/Dutch MSX home computer standard became successful in many countries but not in Britain and the USA, which produced competing systems. Likewise, British and American home computers got no foothold in Japan. These cases may demonstrate both the "not invented here" and the "invented here" syndromes.
An argument for NIH is to guard against an aggressive action by another company buying up a technology supplier so as to create a captive market. This may also guard against future supply issues due to political unrest or other issues.
In programming, it is also common to refer to the NIH Syndrome as the tendency towards reinventing the wheel (reimplementing something that is already available) based on the flawed belief that in-house developments are inherently better suited, more secure or more controlled than existing implementations. This argument is accepted as flawed because wide usage is much more likely to uncover any existing defects than reimplementation. Even more, peer review of source code in the case of a Free Software or Open Source alternative tends to follow Linus' Law: "given enough eyeballs, all bugs are shallow".
In academic environments, the motivation for the NIH effect is twofold: first, resources from student workers are often paid in a lump sum (as a stipend, scholarship, or fixed salary) resulting in no variable increase in pay for more requested work; and second, the drive for publication at some institutions may drive repetition of work done at other institutions or in industry so that the researcher (and institution) may publish about their (repeated) work. Replication is however considered an important element in many areas of science as part of experiment.
The quality of academic products developed from the NIH effect varies widely, mostly for the aforementioned reasons.
Some observers have suggested that the need to keep designers and bureaucrats in work plays an important part in decisions that prefer in-country work.
In the United States, a form of NIH exists in the television industry. A television network affiliated with a particular studio (e.g. ABC and ABC Studios, NBC and Universal Media Studios, CBS and CBS Television Studios, Fox and 20th Century Fox Television) will often buy much, if not most, of its programming from that particular studio, due to the financial benefits of vertical integration.
Conversely, even if a network-affiliated studio's show is picked up by another network, it is not unheard of for the studio to pull out of the series, on the grounds that it represents a large financial investment into a program for the competing network. For example, Touchstone Television (now ABC Studios) pulled out of CSI: Crime Scene Investigation soon after it was picked up by CBS. In other cases, like Medium, the show can still be produced by one network-affiliated studio, and spend its first few years on a competing network, then after being canceled by that network, the producing network can then pick it up (in this case, CBS picked the show up for a sixth season after NBC canceled it).