Garbage in, garbage out
Garbage in, garbage out (GIGO) in the field of computer science or information and communications technology refers to the fact that computers, since they operate by logical processes, will unquestioningly process unintended, even nonsensical, input data ("garbage in") and produce undesired, often nonsensical, output ("garbage out"). The principle applies to other fields as well.
It was popular in the early days of computing, but applies even more today, when powerful computers can produce large amounts of erroneous information in a short time. The first use of the term has been dated to a November 10, 1957, syndicated newspaper article about US Army mathematicians and their work with early computers, in which an Army Specialist named William D. Mellin explained that computers cannot think for themselves, and that "sloppily programmed" inputs inevitably lead to incorrect outputs. The underlying principle was noted by the inventor of the first programmable computing device design:
On two occasions I have been asked, "Pray, Mr. Babbage, if you put into the machine wrong figures, will the right answers come out?" ... I am not able rightly to apprehend the kind of confusion of ideas that could provoke such a question.
More recently, the Marine Accident Investigation Branch comes to a similar conclusion:
"A loading computer is an effective and useful tool for the safe running of a ship. However, its output can only be as accurate as the information entered into it."
- The term can also be used as an explanation for the poor quality of a digitized audio or video file. Although digitizing can be the first step in cleaning up a signal, it does not, by itself, improve the quality. Defects in the original analog signal will be faithfully recorded, but may be identified and removed by a subsequent step by digital signal processing.
- Garbage in, gospel out is a more recent expansion of the acronym. It is a sardonic comment on the tendency to put excessive trust in "computerised" data, and on the propensity for individuals to blindly accept what the computer says. Since the data entered into the computer is then processed by the computer, people who do not understand the processes in question, tend to believe the data they see:
Decision-makers increasingly face computer-generated information and analyses that could be collected and analyzed in no other way. Precisely for that reason, going behind that output is out of the question, even if one has good cause to be suspicious. In short, the computer analysis becomes a credible references point although based on poor data.
- GIGO is also commonly used to describe failures in human decision-making due to faulty, incomplete, or imprecise data. This sort of issue obviously predates the computer age, but the term can still be applied.
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- It is used in audiology to describe the process that occurs at the dorsal cochlear nucleus (DCN) when auditory neuropathy spectrum disorder is present. This occurs when the neural firing from the cochlea has become unsynchronized, resulting in a static-filled sound being input into the DCN and then passed up the chain (hence the "GIGO" nomenclature) to the auditory cortex. 
- GIGO was the name of a Usenet gateway program to FidoNet, MAUSnet, e.a.
|Look up garbage in, garbage out or GIGO in Wiktionary, the free dictionary.|
- "Work With New Electronic 'Brains' Opens Field For Army Math Experts". The Hammond Times. p. 65. Retrieved March 20, 2016 – via Newspapers.com.
- Babbage, Charles (1864). Passages from the Life of a Philosopher. Longman and Co. p. 67. OCLC 258982.
- MAIB (2016-03-17). "SAFETY FLYER" (PDF). MAIB. Retrieved 2016-03-19.
- Quinion, Michael (5 November 2005). "Garbage in, garbage out". World Wide Words. Retrieved 2012-02-26.
- Daniel T. Brooks, Brandon Becker and Jerry R. Marlatt, "Computer Applications in Particular Industries: Securities" appearing in Bigelow, "Computers & The Law", American Bar Association, Section of Science and Technology, Third Edition 1981 at 250, 253.
- Berlin, Hood, Russell, Morlet et al (2010) Multi-site diagnosis and management of 260 patients with Auditory Neuropathy-Dys-synchrony (Auditory Neuropathy Spectrum Disorder)
- jfesler (2001-01-01). "GIGO History". gigo.com/wiki. Retrieved 2014-01-24.