Table 2.

Risk of Bias Summary.

	Random sequence generation (selection bias)	Allocation concealment (selection bias)	Blinding of participants and personnel (performance bias)	Blinding of outcome assessment (detection bias)	Incomplete outcome data addressed (attrition bias)	Selective reporting (reporting bias)
Clark, 2015	?	?	?	?	+	?
Davis, 2011	+	+	+	?	+	?
Duwe, 2014	?	?	?	?	–	?
Employment project,1980	+	+	?	?	+	?
Grommon et al., 2013	+	?	+	?	?	?
Jacobs, 2012	?	?	?	?	?	?
MDOC, 2006	?	?	?	?	?	?
Turner & Petersilia, 1996	?	+	?	?	?	?
Waldo & Chiricos, 1977	?	?	?	+	–	?

Note. + = Low risk of bias; ? = unclear risk of bias; – = high risk of bias.