GIGO

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 flawed, even nonsensical, input data ("garbage in") and produce undesired, often nonsensical, output ("garbage out"). The principle also applies more generally to all analysis and logic, in that arguments are unsound if their premises are flawed.

It was popular in the early days of computing, but applies even more today, when powerful computers can produce large amounts of erroneous data or 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 may have been derived from last-in, first-out (LIFO) or first-in, first-out (FIFO).

"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:

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