Estimating Unidentified Sex Trafficking in the Child Welfare Population

Author: Tueller, Stephen; Gibbs, Deborah & Kluckman, Marianne

Abstract: Sex trafficking involving children is a human rights issue of growing concern, with immediate and lasting impacts on victims. Although victimization is consistently associated with prior maltreatment and foster care placements, reliable estimates of minor sex trafficking prevalence do not exist. In a statewide child welfare database of all children with maltreatment allegations between 2011 and 2016, 3,420 children were investigated for sex trafficking allegations (1.15% of 296,167 children with investigated maltreatment). We used two independent methods to estimate prevalence. A capture-recapture model estimated 3.3% of this population experienced sex trafficking victimization, and due to positive contagion this model is expected to underestimate prevalence. Mixture models predicted sex trafficking victimization for 17.16% of the children, and due to limitations of the data this model is expected to over-estimate prevalence. Findings suggest the prevalence rate of sex trafficking is between 2.9 and 14.9 times the observed rate, even within the state child welfare system that investigates more trafficking allegations than any other. Increasingly sophisticated modeling methods require concurrent efforts to improve identification of sex trafficking within the systems where victims are most likely to be encountered.

Keywords: prevalence, underreporting, child welfare data, administrative data, human trafficking, sex trafficking, mixture model, mark-recapture model