Property offenses figure much larger in the House of Corrections population than in the state prison population — violent offenses are still the largest group at 36%, but property offenses are close behind at 33%, whereas property offenses account for only 9% of the state prison population. Violations of per se drug laws account for essentially the same proportion as at the state level — approximately 15%.
Most state prisoners have committed violent offenses, sex offenses or property offenses. Many people are under the incorrect impression that most offenders in state prison are there for drug offenses, but persons convicted of drug offenses are currently only 15% of the prison population.
Like the state prison population, the House of Correction population swelled rapidly through the 80s and into the 90s. However, the House of Correction population has dropped further from its peak level and now stands at roughly half the DOC population.
Many states have concluded that they have gone past the balance point into the zone of where incarceration costs exceed benefits and they have undertaken reforms to reduce incarceration. Even after their widely admired reforms, their incarceration rates are far above the incarceration rate in Massachusetts. But we cannot infer that Massachusetts is more wisely lenient than other states without a much finer analysis of crime rates and local conditions.
From a 1973 benchmark, the prison population had quintupled to its current level of roughly 10,000 by 1993. One might have expected the prison population to begin falling as crime rates fell through the 90s and into this century. Yet, the prison population has remained fairly stable since 1993. The population committed for the most serious crimes (life sentences or sentences longer than 20 years) has continued to rise steadily, explaining much (but not all) of the continued high number of prisoners.
Several observations (in this post) suggest that the role of legislative enactments in the state prison population increase was limited. Non-legislative factors that could explain the rise include, of course, the stunning rise in crime itself and discretionary responses to that rise by communities, law enforcement and the courts. However, parole board release decisions do not seem to be a likely factor.