Caulkins has conducted research on illicit drugs and the policies surrounding them. In one study, he found that more than 85% of people in prison on drug charges were involved in drug distribution, and that most of the remaining prisoners had some suggestion of involvement in distribution. While at RAND, he also led another study that found that
mandatory sentencing for low-level drug offenders was ineffective because, in Caulkins' words, "most incarcerated drug dealers can be easily replaced on the street." With respect to
marijuana, he has said that, contrary to popular belief, most users of the drug are not college graduates, and that advocates of the drug's legalization tend to overstate its role in crime and violence with respect to drug trafficking from Mexico. ==Recognition==