I'd like to see some hard data on recidivism and prisoner behavior rather than just a warden's informal belief, but it's interesting.
How Knitting Behind Bars Transformed Maryland Convicts | Knitting on GOOD (GOOD)
They started by knitting comfort dolls, which they gave to children removed from their homes because of domestic issues. Then they moved on to hats for kids at the inner-city elementary school many of the prisoners attended, Zwerling says. “If you look at them, they’re covered with tattoos, they’re rough looking, and many of the young guys don't have all their teeth," she says. “But it doesn't feel rough. They’re very respectful and grateful and very happy to knit.”
The prison’s assistant warden, Margaret Chippendale, believes the men involved with KBB get into trouble less often. “It's very positive because you can see when you go into the room, the dynamics of their conversation; very calm, very soothing,” Chippendale says. “It radiates even when they leave the room and go out into the institution.”