A new law will codify clearer guidelines that the Michigan Parole Board has been following when it considers whether to release prisoners considered to be low risks to re-offend.
Gov. Rick Snyder signed the legislation Thursday.
The law, which takes effect in three months, codifies "objective" parole.
The board can deny parole to inmates who show a high probability of release, but only by using a list of 11 "substantial and compelling" reasons.
The Michigan Department of Corrections says the evidence-based approach has led the parole rate to increase by about 7 percent in the last five years, while recidivism has decreased.
Spokesman Chris Gautz says the law will help maintain the projection of a slow, steady decline in the prison population.