This saying points out the fact that a computer can do only what it is programmed to do and is only as good as the data it receives and the instructions it is given. If there is a logical error in software, or if incorrect data are entered, the result will probably be either a wrong answer or a system crash.
Note: The saying is sometimes shortened to “GIGO” (GUY-go).
(GIGO) /gi:'goh/ Wilf Hey's maxim expressing the fact that computers, unlike humans, will unquestioningly process nonsensical input data and produce nonsensical output. Of course a properly written program will reject input data that is obviously erroneous but such checking is not always easy to specify and is tedious to write.
GIGO is usually said in response to lusers who complain that a program didn't "do the right thing" when given imperfect input or otherwise mistreated in some way. Also commonly used to describe failures in human decision making due to faulty, incomplete, or imprecise data.
The expansion "Garbage In, Gospel Out" is an ironic comment on the tendency to put excessive trust in "computerised" data.