There probably has never been a study regarding the statistics of drug treatment versus incarceration that did not show that drug treatment is less expensive and more effective than incarceration.

This study shows that heroin and crack-cocaine addicts commit fewer crimes after receiving treatment, but the same is probably true for those who abuse methamphetamine or any other drug of abuse.  Additionally, and most importantly, the investment goes towards raising the quality of life for the addict and associates.

The point is that treatment works.

“A study in the U.K. found that heroin and crack-cocaine addicts who received treatment for their addictions committed fewer criminal offenses, the Guardian reported Nov. 17.

The study followed 1,500 recently convicted heroin and crack users sentenced to addiction treatment instead of jail. The number of offenses committed by addicts fell by nearly 50 percent after they entered a treatment program. While theft decreased the most, reduction in crime was consistent, with fraud, drug possession, and prostitution all falling by half.”

http://www.jointogether.org/news/research/summaries/2008/uk-study-shows-addiction.html