Researchers have demonstrated that humans are unable to generate a sequence of random numbers that corresponds in a statistical sense to a simple distribution such as the uniform distribution. The purpose of this article is to present the results of research on the generation of random number sequences by humans. The article describes 10 effects found in such studies, mechanisms explaining these effects, and 14 measures (not including modifications) used to detect deviations from randomness in the sequences. The analysis of numerical sequences is not only of academic interest; it can also be used for the purpose of data validation (auditing).