A Review of Prevalence Estimation Methods for Human Trafficking Populations

Abstract

Human trafficking has long-lasting implications for the well-being of trafficked people, families, and affected communities. Prevention and intervention efforts, however, have been stymied by a lack of information on the scale and scope of the problem. Because trafficked people are mostly hidden from view, traditional methods of establishing prevalence can be prohibitively expensive in the recruitment, participation, and retention of survey participants. Also, trafficked people are not randomly distributed in the general population. Researchers have therefore begun to apply methods previously used in public health research and other fields on hard-to-reach populations to measure the prevalence of human trafficking. In this topical review, we examine how these prevalence methods used for hard-to-reach populations can be used to measure the prevalence of human trafficking. These methods include network-based approaches, such as respondent-driven sampling and the network scale-up method, and venue-based methods. Respondent-driven sampling is useful, for example, when little information about the trafficked population has been produced and when an adequate sampling frame does not exist. The network scale-up method is unique in that it does not target the hidden population directly. The implications of our work internationally include the need for documenting and validating the various prevalence estimation methods in the United States in a more robust way than was done in existing efforts. In providing this roadmap for estimating the prevalence of human trafficking, our overarching goal is to promote the equitable treatment and overall well-being of the socially disadvantaged populations who disproportionately experience human trafficking.

Trauma Informed Care: Trafficking Out-Comes (TIC TOC Study)

“…1 The true prevalence and demographics of HT are unknown in the United States, given limitations in identification, reporting, inconsistent definitions, and methodological challenges in researching a “hard to reach” population. 2-4 The National Human Trafficking Hotline received 11 500 cases of HT in 2019, of which 8753 involved sex trafficking and 6684 involved adults. 5…”

“…1 The true prevalence and demographics of HT are unknown in the United States, given limitations in identification, reporting, inconsistent definitions, and methodological challenges in researching a "hard to reach" population. [2][3][4] The National Human Trafficking Hotline received 11 500 cases of HT in 2019, of which 8753 involved sex trafficking and 6684 involved adults. 5 The health consequences of HT are numerous and varied, ranging from sexually transmitted infections (STI); Human immunodeficiency virus (HIV) infection; acute and chronic trauma related to violence, accidents, and overuse injuries; unwanted pregnancy and associated complications, substance abuse disorders, fatigue, and chronic pain, to post-traumatic stress disorder (PTSD), complex PTSD, major depression, suicidality, and anxiety disorders.…”

Sex Trafficking in New York City and Vulnerabilities to Re-Trafficking

“…Globally, an estimated 50 million people are trafficked on any given day (International Labour Organization, 2022), although the true prevalence is difficult to estimate due to its hidden nature. Victims may be reluctant to report their experiences due to fear of retaliation, distrust in the police, or feelings of shame (Hepburn & Simon, 2010; Nemeth & Rizo, 2019; Schroeder et al, 2022). In the United States, the number of calls to the National Human Trafficking Hotline can give insight into the scale of this issue.…”

The Public Health Response to Human Trafficking: A Look Back and a Step Forward

“…4,5 Structural racism, xenophobia, gender inequality, and misogyny magnify this vulnerability. 6 Increasingly, public health strategies drive human trafficking research, 7 including investigations using sophisticated methods of prevalence estimation, 8,9 the design and validation of screening tools, [10][11][12] and the use of sentinel surveillance to detect trends in human trafficking. 13 While much research focuses on identifying risks and vulnerabilities at the individual and relationship levels, 14,15 there is an increasing focus on studying cultural factors that influence human trafficking at the societal level, including systemic racism and other beliefs and attitudes that foster the marginalization of large groups (eg, homophobia, transphobia).…”

“…Multiple studies in this issue highlight the strengths of the public health approach to human trafficking. In their topical review, Schroeder et al 8 compare public health methods of estimating the prevalence of hard-to-reach populations (eg, sex workers, undocumented migrant workers) and discuss implications for human trafficking research. They acknowledge the inherent difficulties in accurately estimating the number of trafficked people regionally and globally and describe tangible (eg, lack of coordinated data systems) and methodological (eg, inconsistent definitions of key terms) challenges.…”