Each study is mapped into the Matrix by a different color-coded circle. These color codes indicate whether an intervention was effective, had mixed results, did not show any evidence of effects, or was harmful:
Effective finding– The study found statistically significant findings that indicated this intervention was effective in reducing crime or criminality.
Example: Problem solving at crime hot spots reduced crime at targeted locations (see Braga and Bond, 2008).
Mixed Results– Some outcomes showed effective findings while others showed no effect of the intervention or backfire effects on crime and criminality. We recognized that most studies may have both significant and nonsignificant findings and coded a study as having mixed results only when the authors emphasized the mixed nature of the findings (see examples below).
Example: Restorative justice reduces recidivism for violent crime but not property crime (see Sherman et al., 2000) or raids on drug distribution houses reduced crime but only for a 12 day period (see Sherman & Rogan, 1995)
No Evidence of Effect – No statistically significant finding was discovered that would indicate the intervention creates an impact on crime or criminality.
Example: DARE program had no significant effects on drug, cigarette or alcohol use (see Rosenbaum and Hanson, 1998).
A Harmful Intervention or “Backfire” – The study found statistically significant findings that indicated this intervention was harmful, leading to an increase in crime or criminality.
Example: Elder abuse programs may lead to increases in victimization (see Davis and Medina-Ariza, 2001).