The evaluation of large volumes of medical data mostly consists of the determination of different frequency information often followed by computing of test statistics. To permit the calculation of this frequency information and, consequently, the analysis of the data during a dialogue, a totally inverted file structure is recommended where the individual data items are stored in bitstrings. The utilization of such a file structure in a problem-oriented programming language—favorable for statistical analysis of the data—can be ensured by eight assembler procedures. These procedures also permit an easy implementation of any optional methods of statistical evaluation based on frequency information.