Conventional law enforcement - including more arrests of drug dealers, confiscations, prosecutions and standard-length prison terms - comes in second, a substantially better investment than the growing use of mandatory minimum sentences, the think tank reported.
"Mandatory minimum sentences are not justifiable on the basis of cost-effectiveness at reducing cocaine consumption or drug-related crime," said the study, "Mandatory Minimum Drug Sentences: Throwing Away the Key or the Taxpayer's Money?"
"Our results indicate that we would make greater drug control progress by sentencing more dealers to standard prison terms than by sentencing fewer dealers to longer, mandatory terms," said the study leader, Jonathan P. Caulkins.
"They also suggest that treatment should receive higher priority than it does today. But the shift toward treatment should not be pushed too far. After all, it often takes enforcement to provide willing clients for treatment."
The study found that because almost the entire cost of treatment occurs in the first year, incarceration initially looks better. But after the second year, as the cost of imprisonment mounts, treatment becomes dramatically more cost-effective as benefits from those who have given up drugs continue without additional cost.