MODELS ARE BASED ON ONE OF TWO BASIC APPROACHES TO THE INDIVIDUAL'S CRIME DECISION. THE PORTFOLIO APPROACH PERTAINS TO THE INDIVIDUAL'S DECISION ON WHAT PART OF HIS WEALTH TO PUT AT RISK IN A CRIMINAL ACTIVITY. AN ALTERNATIVE APPROACH VIEWS THE CRIMINAL BEHAVIOR DECISION AS A TIME ALLOCATION PROBLEM. IN THE PORTFOLIO APPROACH, MODEL ONE, THE INDIVIDUAL CONSIDERS CURRENT WEALTH AND PROBABILITIES OF VARIOUS EXPECTED INCOME INCREASES AND DECREASES, AND ARRIVES AT AN EQUILIBRIUM PORTION OF RESOURCES DEVOTED TO ILLEGAL ACTIVITY. THE MODEL'S RESULTS DEPEND ON CONCEPTS OF RISK AVERSION AND OF ALLOCATION OF SOME BUT NOT ALL OF THE INDIVIDUAL'S RESOURCES TO ILLEGAL ACTIVITIES. THIS MODEL IS STRICTLY APPLICABLE ONLY WHEN GAINS AND LOSSES ARE MONETARY. INCOME REPORTING TO TAX AUTHORITIES IS ONE APPLICATION. THE SECOND MODEL IS A PORTFOLIO MODEL OF TIME ALLOCATION BASED ON THE CONCEPT OF MONETARY EQUIVALENCE OF NONMONETARY FACTORS. THIS MODEL PREDICTS THAT NO REDUCTION OF RETURNS FROM CRIME OR INCREASE IN UNCERTAINTY OF THOSE RETURNS WILL CAUSE PROFESSIONAL CRIMINALS TO ENTER LEGAL OCCUPATIONS. IT ALSO IS LIMITED BY ITS SPECIALIZED CONCEPT OF MONETARY EQUIVALENCE. A THIRD SET OF MODELS, BASED ON THE ASSUMPTION THAT RESULTS OF ILLEGAL ACTIVITY ARE BERNOULLI DISTRIBUTED. PLACES NO RESTRICTIONS ON NONMONETARY ASPECTS OF THE OFFENSE DECISION. THEY, TOO, TREAT CRIMINAL BEHAVIOR DECISIONS AS A TIME ALLOCATION PROBLEM. THE FOURTH MODEL TRIES TO DEAL WITH PROBLEMS FOUND IN THE FIRST THREE. FOR EXAMPLE, REPLACING THE BERNOULLI DENSITY FUNCTION WITH A MORE GENERAL DENSITY FUNCTION PROVIDES A MORE COMPLEX RANGE OF POTENTIAL CONSEQUENCES OF CRIME DECISIONS WHILE RETAINING THE CONCEPT OF CHOICE AS A TIME ALLOCATION PROBLEM. NEVERTHELESS, THE INTENDED SUPPLY DECISION MAY STILL BE THWARTED BY IMPRISONMENT, A POSSIBILITY NOT RELEVANT TO OTHER ECONOMIC MODELS OF SUPPLY. THESE PROBLEMS ILLUSTRATE THE NEED FOR RESEARCH FOCUSING ON THE UNDERLYING DECISION PROCESS RATHER THAN ON THE GENERATION OF AD HOC MODELS. A REFERENCES LIST AND DETAILS OF THE PORTFOLIO MODEL ARE INCLUDED. (CFW)