Measuring the Impact of Services for Human Trafficking Survivors: Tracking Clinically Significant Improvement Across Outcomes

Evaluations of anti-trafficking services typically use statistical significance to determine effectiveness. However, statistically significant increases in quantitative assessments do not necessarily indicate substantive changes in survivors’ lives. This study employs clinically significant improvement as a standard for measuring outcomes among survivors who received services at the Coalition to Abolish Slavery & Trafficking (Cast, N = 167). Analyses focus on Emotional, Medical, Housing, and Social Support needs as measured through a multidimensional assessment administered every three to six months. We operationalize “measurable improvement” as an increase of 0.5 points (12.5 percent of the scale) and “substantial improvement” as an increase of 1.0 point (25 percent of the scale). We use time-to-event analysis to model improvement over time. Median time to measurable improvement ranged from seven to 10 months across dimensions and median to substantial improvement ranged from 12 to 20 months. Labor trafficking survivors had significantly longer timelines to improvement for Medical and Social Support needs than survivors who had experienced both labor and sex trafficking.