It's a cost-effective way of supervising offenders who may no longer need to be locked up to protect public safety, Walsh said. While it costs an average of $35,000 a year to incarcerate someone, it costs roughly $5,000 to keep someone on parole.
And there are new technologies that make it easier to supervise parolees, such as electronic monitoring and GPS systems.
The board has made some efforts to better explain its decisions. While Walsh defended the board's practice of secret votes, citing concerns about safety of individual members, she said the board recently began preparing more detailed decisions, as it did in the Doucette case.
Still, it's not a perfect system, she acknowledges. Board members ultimately have to rely on their own judgment.
And, she said, there are some inmates who are not, and probably never will be, fit to live in society.
"Sometimes the system is not fair," Barton said. "It's run by human beings, and we as human beings, make mistakes."