New York's system differs from other cities in some other costly ways — it employs 9,000 relatively well-paid, unionized correction officers, for example, and is required by law to provide certain services to inmates, including high quality medical care within 24 hours of incarceration.
Nick Freudenberg, a public health professor at Hunter College, said the latest city figures show that declining incarceration rates haven't translated into cost savings.
In 2001, when the city had 14,490 inmates, the full cost of incarcerating one inmate at Rikers Island for a year was $92,500, or about $122,155 adjusted for today's dollars — that means the city spent $45,576 more in 2012 than it did 11 years ago.
"To my mind, the main policy question is: How could we be spending this money better?" Freudenberg said. "What would be a better return on that investment?"
Another contributing factor to the inmate price tag is the length of stay for prisoners in New York's criminal justice system. Some inmates have waited years in city jails to see trial. The DOC said in 2012 that the average length of stay for detainees was 53 days and 38.6 days for sentenced inmates.
"Not only is that a miscarriage of justice, it affects your operations," said Michael Jacobson, a former commissioner of the city's Department of Correction and probation who serves as director of the CUNY Institute for State and Local Governance. "You want to save big money? Take a quarter out just by improving the process they go through when they're in the system."