Human Rights Watch examined the recidivism rates of NYC residents arrested for possession of marijuana:
We tracked through mid-2011 the criminal records of nearly 30,000 people without prior criminal convictions who were arrested in 2003 and 2004 for marijuana possession. As shown in the figure [above], we found that 3.1 percent of them were subsequently convicted of one violent felony offense during the six-and-a-half to eight-and-a-half years that our research covers; 0.4 percent had two or more violent felony convictions. That is, 1,022 persons out of the nearly 30,000 we tracked had subsequent violent felony convictions. Ninety percent (26,315) had no subsequent felony convictions of any kind.
There is no readily available data on the rates of felony or violent felony conviction for comparable demographic groups in New York City who do not enter the criminal justice system on marijuana charges. But the rate of felony and violent felony conviction among this group of first-time marijuana arrestees appears to be lower than the rate of felony conviction for the national population, taking into account age, gender, and race.