Professional updating processes can be visualized as a system enabling both educators and professionals to enhance individual competence. The systems analysis model given here represents updating practices both pictorially and mathematically. Strengths of the model are: it incorporates educational, psychological, and motivational factors from a systems viewpoint; the mathematical model enables the determination of the most influential variables in the updating process; the model can be developed for both individuals and groups; and parameters of mathematical models can be estimated or determined with standard statistical procedures. Weaknesses are: the model is somewhat simplified and may not include all possible parameters; negative feedback is not recognized; the problem of statistical estimation of parameters is still unresolved; and the assumption that updating is a consistently nondecreasing process can be questioned. (Seven figures are included.) (ly)