The data found in medical records, particularly in problem-oriented records, could yield very useful information for many aspects of the health care delivery system. Unless the tools and methods used in the analysis of health care data are very carefully designed, the potential value of this information cannot be fully realized. Coding is a critical step in the process of converting medical record data into useful information. This paper presents six criteria as design goals for a standard, comprehensive, coherent set of nomenclatures, classifications, taxonomies, and corresponding coding schemes for the analysis of medical and administrative record data. These goals are: compatibility with established routine operating procedure, health care problem specificity, hierarchical structure, economy through articulation of the components with one another and through the similarities in various aspects of health care delivery, and adaptability to change.