The study follows a cohort consisting of 15,117 individuals from the age of 15 years through the age of 30 years. The age-based transition probabilities are studied, both for males and for females, showing that the transitions for females conform to a first-order Markov chain, so that the original matrices can be seen as estimates from a single "parent matrix." This was not the case for males. The predictive power of prior criminality for later transition probabilities is also studied. Finally, the difference between stating that a given percentage will relapse in crime and the ability to make real prediction is emphasized. 15 tables, 17 references. See NCJ 124605-124612 for individual papers. (Author abstract)