Garbage In, Garbage Out (abbreviated to GIGO, coined as a pun on the phrase First-In, First-Out) is a phrase in the field of computer science or information and communication technology. It is usedprimarily to call attention to the fact that computers will unquestioningly process the most nonsensical of input data (garbage in) and produce nonsensical output (garbage out). It was most popular inthe early days of computing, but applies even more today, when powerful computers can spew out mountains of erroneous information in a short time. The actual term "Garbage in, garbage out", coined asa teaching mantra by George Fuechsel, an IBM 305 RAMAC technician/instructor in New York, was soon contracted to the acronym "GIGO". Early programmers were required to test virtuallyeach program step and cautioned not to expect that the resulting program would "do the right thing" when given imperfect input. The underlying principle was noted by the inventor of the firstprogrammable 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 toapprehend the kind of confusion of ideas that could provoke such a question.
—Charles Babbage, Passages from the Life of a Philosopher
It is also commonly used to describe failures in humandecision making due to faulty, incomplete, or imprecise data.
The term can also be used as an explanation for the poor quality of a digitized audio or video file. Although digitizing can be thefirst 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.(See 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 "computerized" data, and on...