Although they are the only broad studies focusing on the effects of decriminalization, the Oregon, California, and Maine surveys have serious methodological problems regarding their time frames, questionnaire design, sampling methods, and variables selected. Specifically, they failed to control adequately for age and other variables such as sex, income, and education thought to influence the prevalence of marijuana use. Other areas neglected or not given suffficient attention included frequency, intensity, and duration of marijuana use. The limited evidence does indicate, however, that intensified or compulsive marijuana use patterns will not occur following decriminalization, although those aged 18 to 29 appear to be at the highest risk in this respect. More research on the effects of more lenient laws on younger age groups is needed to evaluate the consequences of removing criminal sanctions. No decriminalization studies have adequately addressed the age of onset of marijuana use and its relation to duration and intensity of use. Decriminalization might be perceived as an official sanction of marijuana use, thus encouraging increased consumption, and increasingly favorable attitudes toward marijuana were indeed noted in Oregon and California. Finally, no surveys have used samples from States retaining penalties for marijuana possession to determine patterns of use. The papers include 20 footnotes.