A precalculated error budget, plus an assist from the systems computer, provides fast checkout of a computer-based data-acquisition system design. The resulting test is easy to apply, yet it takes full account of the complex specifications for individual analog-input devices, such as multiplexers and digitizers. With the error budget, the allowable mean and rms errors of the entire system can be predicted. The computer calculates mean and rms values from data samples collected while operating with a calibrated input source. Comparison of computed values with calculated maximum sample means and standard deviations reveals the errors. In a few minutes, thousands of samples on many channels can be taken, digitized and printed out.