Proceedings of a Workshop

Estimating the Prevalence of Human Trafficking in the United States: Considerations and Complexities

Proceedings of a Workshop—in Brief

Dorothy Fink (Deputy Assistant Secretary for Women’s Health and the Director of the Office on Women’s Health at HHS) underscored the salience of reducing and preventing human trafficking victimization to her office’s goal of improving health conditions for women and girls across the United States. She said the conditions to which human trafficking victims are subjected—such as dangerous work environments, exposure to communicable diseases, lack of access to adequate health care, and physical and mental abuse—can have profoundly negative implications throughout the victims’ lives. Fink called the issue a bipartisan congressional priority, and she highlighted the passing of the Trafficking Victims’ Protection Act (2017) and the Put Trafficking Victims First Act (2019) as necessary steps toward developing methodologies to assess the prevalence of human trafficking.

Before we can assert credible influence on policy making or legislations, we need to first and foremost develop counting rules or diagnostic criteria. How we count trafficking violations will also bear significant consequences on our estimations of a prevalence or baseline estimation. (Sheldon Zhang, Planning Committee Member)

DEFINING HUMAN TRAFFICKING

Human trafficking has many names—pimp control, commercial sex, exploitation, forced labor, modern slavery, child labor, and several others—and can take many forms: The definitions vary greatly across countries and cultures, as well as among researchers. The most definitive voices come from the United Nations and the International Labour Organization (ILO), which have emerged as leading global voices on defining and addressing human trafficking.

As part of its 2030 Agenda for Sustainable Development, the United Nations created 17 Sustainable Development Goals (SDGs),¹ each with specific and measurable targets. Target 8.7 calls for effective measures to end forced labor in all forms by 2025, and Target 5.2 addresses violence against women, including trafficking and sexual and other types of exploitation. The ILO, the Walk Free Foundation, and several other counter-trafficking agencies use Targets 8.7 and 5.2 as guiding principles for their research.

Patterned after Target 8.7, the U.N. University Centre for Policy Research (UNU-CPR) created an online human trafficking research and information tool called Delta 8.7. Kelly Gleason (UNU-CPR, ILO) said the tool is designed to help policy actors efficiently access and digest data most relevant to policy making and to identify what type of policy efforts work to eradicate forced labor, child labor, modern slavery, and human trafficking.

Michaelle DeCock (ILO) explained that the ILO’s definition of forced labor consists of three critical components: (1) performing work or service, (2) the involuntariness of the work or lack of concern on the part of the employer (i.e., making false promises), and (3) the menace of any penalty used to compel the person to work. This definition has not changed since 1930,² but in 2014, the ILO added a forced labor supplementary protocol for preventing human trafficking and sexual exploitation: The protocol reinforces how forced-labor has changed over the years. In 2008, the ILO also released Hard to See, Harder to Count,³ which provides survey guidance for human-trafficking data collection.

UNDERSTANDING VULNERABILITY AND DEMAND

Megan Lundstrom (Free Our Girls) spoke candidly about her experience as a survivor of pimp-controlled and survival sex trafficking. She said that pimp-controlled trafficking mirrors cultic theory in many ways: One is that it has a hierarchy, a strong “us versus them” mentality. In addition, pimps have the ability to create a false sense of normalcy for their victims by allowing them a degree of autonomy, though it is heavily monitored. Lundstrom found her freedom in 2012, but she said she had difficulty transitioning into school and the workforce because she was a single mother, had been diagnosed with posttraumatic stress disorder, had a decade-long gap in work experience, and had 10 arrests on her record.

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¹See https://sustainabledevelopment.un.org/sdgs.

²C029 - Forced Labour Convention, 1930 (No. 29). See: https://www.ilo.org/dyn/normlex/en/f?p=NORMLEXPUB:12100:0::NO::P12100_ILO_CODE:C029.

³Hard to See, Harder to Count: Survey Guidelines to Estimate Forced Labour of Adults and Children. See: https://www.ilo.org/wcmsp5/groups/public/---ed_norm/---declaration/documents/publication/wcms_182096.pdf.

When Lundstrom left “the game,” she stayed in contact with women she knew who were still active, and through sharing experiences, her social network grew to more than 1,600 actively exploited women in the United States and Canada. Her organization now provides assistance and intervention support to these women through its private network.

Jessica Hubley (AnnieCannons), whose organization works with survivors of trafficking, said she believes that most, if not all trafficking, exists at the confluence of vulnerability, demand for illicit labor or sex, and exploiters, who are incentivized to exploit the vulnerable to meet that demand. Her agency targets vulnerability by providing survivors with job training and paying them incomes high enough to lift them and their families out of the cycle of exploitation. The organization is also working on a pilot software program that will allow survivors to manage their own personal data and permit access to providers on a case-by-case basis.

The Walk Free Foundation created a Global Slavery Index (GSI), which measures the size and scale of modern slavery and assesses country-level vulnerability and governmental responses.

Davina Durgana (Planning Committee Member) said the GSI operates by the understanding that in order for modern slavery to occur, there needs to be a vulnerable victim, a motivated offender, and the absence of a capable guardian. Walk Free’s risk profile was developed based on GSI’s Vulnerability Model,⁴ which maps 23 risk variables across five major dimensions: (1) governance issues, (2) lack of basic needs, (3) inequality, (4) disenfranchised groups, and (5) effects of conflict. GSI also has a component that assesses the actions governments are taking to respond to modern slavery by measuring their progress towards the achievement of five milestones, one of which is for “Government and business [to] stop sourcing goods and services produced by forced labour.”

Durgana also noted how having a global comparative analysis can be beneficial to prevalence estimation when it is used as an exercise in scale. It can help researchers go beyond the numbers by providing more widely understood interpretations of the magnitude of the problem in particular areas. She added that the global challenge is to look systematically at the networks between nation states and the fluidity across borders that is increased by improvements in technology and transportation and to be able to identify places where national security breaches can still occur.

IDENTIFYING VICTIMS

If we don’t know what we are looking for, it is really hard to see what is in front of us. (Kelly Dore, National Human Trafficking Survivor Coalition)

Kelly Dore (National Human Trafficking Survivor Coalition [NHTSC]) shared her experiences as a victim of familial trafficking from the ages of 1 to 14 years old. When she was 15, she testified in court, and the trafficker—her father—pled guilty to 19 of 27 trafficking charges. Because there were no formal laws in place for human trafficking at the time, her father spent 2 months in jail and did not have to register as a sex offender. Dore did not realize that what had happened to her qualified as human trafficking until she was much older, and she said that is the case for many victims. She said the NHTSC serves to empower survivors through legislative policies and to educate lawmakers on best policy practices. It also provides emergency funding for survivor-led organizations and works to help labor trafficking victims who are stuck in unethical working situations. Dore and Lundstrom serve on the appropriations committee of United Against Slavery (UAS), a coalition that is developing

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⁴ The Global Slavery Index: 2018 Vulnerability Model. See: https://www.globalslaveryindex.org/2018/methodology/vulnerability.

a National Outreach Survey to help identify challenges among those working to combat human trafficking. UAS has partnered with more than 26 representatives of stakeholder groups, including government officials, health care professionals, hospitality workers, human trafficking survivors, and law enforcement officials.

Durgana noted that the way policies are enacted and advocacy campaigns are managed can have clear effects on how people see themselves when it comes to identifying as victims. She has seen significant discrepancies in self-reported data: There are men in Argentina who report as victims of labor trafficking because they are forced to work paid overtime, while there are people in the Congo that report working in legally prohibited and extremely dangerous mining situations with compromised food and water sources who do not identify as victims. She said that victims sometimes rationalize the situation by thinking: “This happened to my father, this is happening to my uncles and brothers, it happens to everyone I know.”

Identifying victims is further complicated by a lack of visibility for certain forms of trafficking. When Hanni Stoklosa (HEAL Trafficking) asked the workshop participants to consider what it would take to make child labor trafficking a priority in data collection in the same way that agencies have prioritized the commercial sexual exploitation of children. Meredith Dank (John Jay College of Criminal Justice) responded that the lack of a concise definition and variations in state laws makes it difficult to address child labor in the United States as its own research problem. Annick Febrey (Human Trafficking Institute) said that a large portion of her agency’s appropriations is designated specifically for sex trafficking. She is unsure whether sex trafficking is prioritized over labor trafficking because sex trafficking cases are often more visible and clear-cut, and therefore are detected more often, or if the increased funding and focus is what enables researchers to find more cases.

Erin Klett (Verité) told the group that her organization uses a sector-based approach to understand labor trafficking victimization. It has conducted research in 15 labor sectors throughout 20 countries and uses the results to develop recommendations and advocate for new policy. When Verité begins a study, the investigators first identify vulnerability indicators that may be relevant to the labor sector in which they are conducting the study. Verité uses the ILO guidance to develop preliminary definitions of how those indicators may present themselves, and it then creates a survey that asks respondents about the presence or absence of each indicator. This approach allows the organization to get a sense of whether there is a risk of forced labor or human trafficking among a certain population of workers, as well as how that risk can be reduced or eliminated. It also allows Verité to document the presence of risk even in cases in which a worker might technically not be in a condition of forced labor or human trafficking at that moment but could be highly vulnerable to it.

COLLECTING PREVALENCE DATA

Point-of-Crisis Contacts

Sara Crowe (Polaris) said that the U.S. National Human Trafficking Hotline, a program run by Polaris and funded by HHS, generates one of the largest lists of human trafficking victims in the country. The hotline operates 24 hours a day, and since 2007, it has received reports on more than 50,000 trafficking victims. She noted that even though the data are self-reported and useful in understanding the nature of human trafficking, the primary function of the hotline is to link victims with support services, not to collect specific data. Crowe noted that there is a difference between the data needed to carefully define an issue and the data needed to respond to it. In addition, data collected during a point of crisis will often be different in nature from information obtained when a survivor is surveyed in a more stable

situation. Health care providers can also use the hotline, which allows them to both report data and to obtain useful information to share with their patients.

Hanni Stoklosa (HEAL Trafficking) said that, as the organization’s executive director, she has used the hotline for this purpose. She noted how the intersection of human trafficking and health presents unique opportunities for prevalence estimation, but that it also presents several challenges. As with other vulnerable populations, trafficking victims often come to the attention of health care providers through emergency rooms like the one in which she works as a physician. In order for trafficking to be reported and captured in a patient’s record, health care professionals need to know how to assess trafficking victimization, and the victim has to disclose the trafficking. There is further difficulty in that this situation assumes that the victim had the opportunity to access the health system in the first place.

HEAL has partnered with HHS on several initiatives that increase the capacity of health care providers to identify trafficking victims. Stoklosa said that despite receiving education about trafficking, doctors are human, and their unconscious biases have the potential to impede their ability to identify a victim in a clinical setting. She noted how trauma presents itself differently in different individuals and said that the media can also shape people’s perceptions of what a victim looks like. She suggested using open-ended and compassionate statements to build trust.

Michael Shively and Ryan Kling (Abt Associates) reported on a study, funded by the National Institute of Justice (NIJ), that looked at the feasibility of collecting human-trafficking prevalence data from vulnerable populations in such settings as homeless shelters, emergency rooms, and correctional facilities. The study screener questions also asked if respondents had been subjected to force (but not fraud or coercion), and the survey asked adults about contact with various social systems (e.g., shelters, drug and alcohol treatment, child and family services, faith-based organizations, and immigration) over their lifetimes. The study showed that all of the individuals identified as trafficking victims (7% of those surveyed) had made contact in the past 12 months with the health care system, social services (such as the Temporary Assistance for Needy Families Program), and the justice system. Shively called these prior points of contact missed opportunities—earlier instances when individuals could have been identified as trafficking victims if routine screening had been conducted and when they could have received support services.

Kling noted some of the challenges to this approach, such as having to use different weights in the estimate for different settings. For example, he and Shively found that shelters had lower turnover rates than jails, but they also found that individuals who were interviewed in jail had a higher probability of having come into contact with another one of the social systems being surveyed. Shively also acknowledged that the method they chose could potentially work against finding people who are currently trafficked because current victims may have less access to care, less mobility, and may still be actively under the control of a trafficker.

Surveys and Sampling

Dank described some of the labor trafficking and commercial sex trafficking studies she has conducted on grants from federal agencies, including HHS, NIJ, and the Office of Juvenile Justice and Delinquency Prevention. The studies used a range of methodologies, including economic modeling, personal interviews, and respondent-driven sampling. She noted that respondent-driven sampling helped tap into hidden populations and learn more about groups not being captured in traditional studies. With support from HHS, she developed and validated a sex and labor trafficking screening tool that was specific to runaway and homeless youth. Dank also used multiple systems estimation to conduct a study on trafficking prevalence in the United States; however, in the absence of a centralized referral

database she had to rely on data collected by various service providers and law enforcement agencies, which was not always a fruitful endeavor. She noted that data sharing is not something that is done well across agencies, and looking for overlap among these datasets proved challenging because of differences in the way human trafficking is defined, investigated, and prosecuted.

Kyle Vincent (Simon Frasier University) talked about the benefits of network or referral-based sampling techniques, and he described an innovative method he derived from these strategies. His method uses administrative data to generate the initial sample, looks at links both within and projecting from the sample, and extrapolates those characteristics to the larger population. He explained how referral-based sampling can illuminate potentially untapped social networks by exploiting direct linkages and capturing individuals who may be missed through traditional sampling designs. He explained that he developed the new method to address the need for an efficient estimate for the population size and to generate a dataset robust enough for more sophisticated network analysis. The start point of the linkages can be modified, and the process can also be adapted with each wave to capture individuals of greater interest. He and his colleagues tested his method on existing datasets in both the United States and abroad, such as empirical datasets based on injection drug users and commercial sex workers, and found it to provide efficient estimates of population size.

Multiple Systems Estimation

Bernard Silverman (Planning Committee Member) posed four questions to the workshop participants: (1) How do we analyze data when many characteristics we would like to know are not available? (2) How might results be presented to policy makers and the wider public? (3) Is there any advantage to making data available in an easily available public repository so that there can be further research? (4) What are the features of the data in this area that demand specific methodology?

In his role as the Chief Scientific Adviser to the U.K. Home Office, Silverman applied multiple systems estimation to data from the U.K.’s National Referral Mechanism, arranged into five primary source groupings for human trafficking contact: (1) local authorities, (2) nongovernmental organizations, (3) governmental organizations, (4) law enforcement agencies, and (5) the general public. His approach used a mathematical model to estimate the number of cases not captured on any of the lists—also known as the “dark figure.”⁵ Silverman said that using multiple systems estimation essentially quadrupled the initial estimate of human trafficking victims because it included as-yet-unidentified victims. He said that he believes that researchers can effectively communicate this kind of uncertainty to policy makers if they work closely together and build trust. Silverman discussed his attempt to conduct similar research in New Orleans and how trepidation from agencies over releasing their data prevented the researchers from obtaining a robust dataset. He talked about specific methodologies he used for sparse data tables and emphasized the importance of making data accessible in the public domain for transparency and future research.

James Johndrow (Stanford University) discussed his work on casualty estimation, conflict mortality, and methods to measure hidden populations. He used the term “capture-recapture heterogeneity” to describe how, in multiple systems estimation, not all of the individuals have the same probability of being observed in a sample. If someone with a low likelihood of being observed appears in the data, it could be an indication that several similar cases exist. He referred to the unknown number of people who are not captured in the data at all as “Big K” (the equivalent of the “dark figure,” discussed above). Johndrow explained

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⁵ See Biderman, A., and Reiss, A. (1967). On exploring the “dark figure” of crime. The ANNALS of the American Academy of Political and Social Science, 374(1), 1-15.

to the workshop participants that once the probability of appearing on any list is calculated, he can apply a multiplier to calculate the total population’s size. If the probability of being observed is low, the multiplier is high; if the probability is high, the multiplier decreases proportionately. He said that the reality of measuring hidden populations is that if people are close to invisible, they cannot be estimated—but their possible existence needs to be explicitly incorporated into research models in order to achieve reasonable confidence intervals.

COORDINATING DATA COLLECTION EFFORTS ACROSS AGENCIES

Several of the organizations with representatives at the workshop have long-standing histories of collaboration on counter-trafficking enterprises, which they hope to build on in order to achieve the goal of creating a cohesive strategy for research on the prevalence of human trafficking. Those attendees discussed four of the prominent partnerships: (1) global estimates of modern slavery; (2) the work of the International Conference of Labor Statisticians (ICLS), (3) the Research Action Project, and (4) the Counter Trafficking Data Collaborative.

Global Estimates of Modern Slavery

DeCock told the group that in 2017 ILO, in collaboration with the Walk Free Foundation and the International Organization for Migration (IOM), published the Global Estimates of Modern Slavery.⁶ To obtain the estimate, they used a combination of methodologies on national datasets in more than 50 countries and on data from IOM’s database on victims of trafficking for forced labor and sexual exploitation. In addition to these global estimates, ILO is continuing to work with IOM and the U.N.’s Office of Drugs and Crime to develop a standardized definition and specific tools for the measurement of trafficking for forced labor.

International Conference of Labor Statisticians

DeCock also described work of the ICLS, which in 2013 created a working group to test new measurement tools and create a set of guidelines. The guidelines were formally adopted in 2018, along with a unique statistical definition of forced labor. She noted that several workshop participants are also members of ICLS.

Research to Action Project

The Research to Action Project is an initiative funded by the U.S. Department of Labor designed to examine the state of available human trafficking data, highlight gaps in knowledge, and communicate findings to policy makers. The project, which involves input from IOM and UNU-CPR, is intended to build greater research capacity and interest among researchers across disciplines to study forced labor, child labor, and human trafficking through grants and online educational tools. Gleason said that the project is mapping past and current research efforts to research funding sources, which will inform national and global research agendas.

Counter Trafficking Data Collaborative

Harry Cook (International Organization for Migration) said that IOM, the U.N.’s migration agency, provides return, reintegration, and repatriation assistance to upwards of 8,000 trafficking victims every year in more than 150 countries. Cook said the objective of the IOM, and the Counter-Trafficking Data Collaborative (CTDC), to which it belongs, is to create a greater culture of openness around data. He said it is important to be clear about the reason the data are being collected, by whom, and for what purpose.

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⁶ International Labour Organization. Global Estimates of Modern Slavery: Forced Labour and Forced Marriage. 2017. See: https://www.ilo.org/wcmsp5/groups/public/---dgreports/---dcomm/documents/publication/wcms_575479.pdf.

Funded by the U.S. Department of State, the CTDC is a global data repository of de-identified data for access by researchers and policy makers at a global scale. IOM, Polaris, and Liberty Shared are primary data contributors. Crowe said that creating the repository required the three organizations to reconcile definitional differences: Polaris uses the definitions in the U.S. federal Trafficking Victims Protection Act, while IOM and Liberty Shared use European definitions that include forced marriage and organ trafficking. The CTDC is a combined dataset of 91,000 records. Its two primary outputs are a visual dashboard for aggregate data and a downloadable, de-identified, and disaggregated dataset.

FEDERAL GOVERNMENT INITIATIVES

Lauren Damme (U.S. Department of Labor) told participants that the Office of Child Labor, Forced Labor, and Human Trafficking, which is housed in the department’s Bureau of International Labor (ILAB), was formed to promote a fair global playing field for workers in the United States and around the world by enforcing trade commitments, strengthening labor standards, and combating international child labor, forced labor, and human trafficking.⁷ One of the office’s major research products is an annual report of the findings on the worst forms of child labor, authorized by the Trafficking Victims Protection Act, which currently includes a list of 148 goods produced by forced labor, child labor, and forced child labor. Damme said impact evaluations conducted in Nepal to measure the effectiveness of mass media campaigns in decreasing vulnerability to child and forced labor found that danger narratives—ones portraying the victims in hopeless situations—were much less effective in reducing vulnerability than empowerment narratives that showed victims finding support to get out of trafficking situations.

Carolyn Huang (U.S. Department of Labor) said ILAB’s technical cooperation projects create tools for forced labor research and help countries increase their capacity to work with the ILO to produce data at nationally representative levels. In Brazil, ILAB funded a study of 2,000 households that looked at forced labor and hereditary slavery. As a result of this survey, Brazil is now trying to incorporate a forced labor module as part of their National Health Survey and to learn more about the linkages between forced labor and health. Huang talked about similar studies that ILAB supports in Nepal, Malaysia, and Peru, as well as a collaboration between the ILO, UNICEF, IOM, and Walk Free to understand children in armed recruitment. ILAB is providing support to expand and house their various research tools on the U.N.’s Delta 8.7 platform.

Carolyn Hightower (U.S. Department of Health and Human Services) discussed the work of the department’s Office of Trafficking in Persons (OTIP). OTIP’s mission is to combat trafficking by supporting systems that prevent trafficking through public awareness and to protect victims through identification and assistance. Guided by the Trafficking Victims Protection Act and several other statutes, Hightower said OTIP has three primary functions: (1) victims’ protection, (2) trafficking prevention, and (3) research and policy. Hightower noted that human trafficking is a public health issue that affects individuals, families, and communities and that research and data collection are critical to strengthen the nation’s response. In collaboration with the Office on Women’s Health in DHHS, OTIP is implementing the Human Trafficking Data Collection Project to establish uniform data collection standards across anti-trafficking grant programs and to integrate human trafficking into existing datasets for child welfare, runaway and homeless youth, refugee resettlement, and health care service systems.

Patrick Hannon (Human Smuggling and Trafficking Center) said his agency is the only legislatively directed national federal anti-trafficking center in the United States. Its goal is

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⁷ ILAB uses the ILO definition of forced labor.

to develop and deliver intelligence to law enforcement and policy makers to help respond to the hard problems surrounding human trafficking. He noted that the goal is particularly challenging because of the lack of a clear understanding of the priorities and gaps that exist in this research community. Hannon emphasized the importance of clear and effective dissemination: the data need to matter to law and policy makers so they are motivated to use the findings, advocate for human trafficking research, and allocate resources to continued research and intervention.

Amy Leffler (National Institute of Justice) told participants that NIJ’s Trafficking in Persons Research Program has operated for close to two decades and is committed to informing stakeholders on the trafficking evidence base and evaluating what counter-trafficking measures work. Through funding and disseminating rigorous research, NIJ aims to build the evidence base on areas such as prevalence, demand, screening, and victim service, in an effort to bolster human trafficking detection, prosecution, law enforcement, and court practices. Recent research aims to tackle prevalence through examining specific populations in specific jurisdictions, while using innovative statistical methods, such as multiple systems estimation and respondent-driven sampling, to see how lessons learned abroad and in other fields can be applied to the United States. Leffler noted that prevalence is just one piece of a very complex puzzle, and that the research community should work with stakeholders from different academic disciplines, law enforcement, and victims’ services to determine what methodological approaches work for each population.

LINKING PREVALENCE TO POLICY

Sheldon Zhang (Planning Committee Member) said that human-trafficking prevalence estimation essentially boils down to two basic questions: What to count and how to count it? He noted how there is no diagnostic manual, akin to the DSM-5 for mental disorders or the ICD-10 for diseases, for human trafficking. Thus, most researchers in this field construct instruments specific to their research projects, either in response to their own understanding of the issues at hand or to their respective agency mandates. Zhang also discussed what he called a perennial threshold problem: Most crimes are defined and studied as individual incidents, but human trafficking cannot be as easily defined. What, then, is the threshold over which a series of incidents amount to trafficking? He asked the workshop participants to consider the possibility of agreeing on a set of core measures that can be used as the basic threshold over which one can define these types of human rights violations. How trafficking violations are counted will bear significant consequences on prevalence or baseline estimation.

Roy Ahn (Planning Committee Member) spoke on his experience conducting human trafficking research across health and nonhealth sectors. He noted how health-care data collection is expansive and largely driven by the advancement of electronic health records. Health-care data sharing occurs at the aggregated, anonymized level for public health and at the individual level for practitioners dealing with patients in crisis. In 2018, the ICD-10 added codes for suspected and confirmed cases of labor and sex exploitation, which Ahn said has the potential to increase agencies’ incentives for collecting and utilizing these data. He noted how there has been a push in health care to begin collecting data on the social determinants of health, which could lead to a better understanding of the vulnerabilities that cause individuals to fall victim to trafficking. Ahn said he hopes this will enable providers to create better trauma-informed models for health care or for community-level prevention, and he noted that those are both ways of potentially linking prevalence to policy.

Abby Long (U.S. Department of State) explained that the Office to Monitor and Combat Trafficking in Persons (TIP) partners with foreign governments, international organizations,

other federal agencies, civil society, the private sector, and survivors of human trafficking to develop and implement effective strategies to confront modern slavery. She said that prevalence estimates produced from a combination of rigorous research, expert consultation, and peer review can provide an improved picture of the problem and a better understanding of the resources it will take to fight human trafficking. An accurate prevalence estimate can help researchers explain funding goals to Congress, stakeholders, and to the general public. Long said she believes the connection between research and policy can be strengthened by focusing on three key components. First, she said, prevalence estimation needs to be done using the guiding principles of rigor, ethical considerations, replicability, and transparency. Second, prevalence work needs to be paired with robust monitoring and evaluation, which could receive its own funding. And third, prevalence studies could use an impact evaluation methodology to effectively identify what factor or combination of factors result in decreases or increases in prevalence estimates.

Manisha Shah (University of California, Los Angeles) explained to the workshop participants that she regularly conducts impact evaluations and randomized controlled trials to study sex trafficking throughout the world. Recently, she has worked with administrative data and using web scraping techniques in her U.S. research. Shah said estimates from her research suggest that approximately 80 percent of women engaging in commercial sex are using online markets and mobile messaging apps. She noted that the Defense Advanced Research Projects Agency has devoted money to dark web mining, and she believes this work could be a way forward in the fight to combat trafficking. She acknowledged that variations in agencies’ definitions of human trafficking and conflation between the global definitions of sex work and sex trafficking can complicate data analysis. Shah said that she is a proponent of using a combination of data collection methods to best capture prevalence in varying contexts, and she noted that respondent-driven sampling and longitudinal studies conducted in several countries, including Indonesia and Ecuador, have proven in some cases to be as valuable as such methods as multiple systems estimation.

Febrey said her organization, the Human Trafficking Institute, tackles impunity for traffickers by working through the public justice system. The institute currently operates in Belize and Uganda, working with local governments to develop specialized police units, within the countries’ existing law enforcement agencies, that focus only on trafficking cases. The institute’s goal is to reduce human trafficking by 10 percent in these countries by increasing prosecution of human trafficking cases and potentially deterring future traffickers. The organization uses three indicators to quantify its impact: (1) the number of cases going through the justice system, (2) the country’s ranking on the Department of State’s TIP report, and (3) prevalence estimates. She said the institute also regularly uses prevalence data in its policy advocacy.

REMEMBERING WHY THIS RESEARCH MATTERS

David Banks (Planning Committee Chair) reinforced the notion that while human-trafficking prevalence estimation is an important tool for leveraging resources, garnering attention from policy makers, and coordinating law enforcement efforts, it alone will not solve the problem. Preventing human trafficking will require coordination across disciplines and fields.

Hubley reminded the workshop participants that the ultimate goal of research efforts is to maximize survivor well-being. She said research is most valuable to survivors if it is used to direct resources to their care. She urged researchers to consider survivor safety, both in the data collection process and with the safeguarding of their personal information, and to put more emphasis on studying vulnerability as a means of prevention.

Dore spoke on the importance of empowering survivors to take charge of their own healing. She listed five key steps: (1) meet their basic needs; (2) avoid retraumatization during interviews and interventions; (3) be conscious of language used during interactions with survivors; (4) work to build trust and rapport; and (5) remain sensitive to power dynamics, considering the survivors have likely just left a highly controlled environment. She said most of these keys can be accomplished by providing support and education for service providers.

PLANNING COMMITTEE FOR THE WORKSHOP ON APPROACHES TO ESTIMATING THE PREVALENCE OF HUMAN TRAFFICKING IN THE UNITED STATES

David Banks (Chair), Department of Statistical Science, Duke University; Roy Ahn, NORC at the University of Chicago; Katherine Chon, Administration for Children and Families, U.S. Department of Health and Human Services; Davina Durgana, Walk Free Foundation; Megan Price, Human Rights Data Analysis Group; Sir Bernard Silverman, School of Politics and International Relations, University of Nottingham; and Sheldon Zhang, School of Criminology and Justice Studies, University of Massachusetts, Lowell.

DISCLAIMER: This Proceeding of a Workshop—in Brief was prepared by Jordyn White, rapporteur, as a factual summary of what occurred at the meeting. The statements made are those of the rapporteur or individual meeting participants and do not necessarily represent the views of all meeting participants; the planning committee; the Committee on National Statistics; the Committee on Population; or the National Academies of Sciences, Engineering, and Medicine. The committee was responsible only for organizing the public session, identifying the topics, and choosing speakers.

REVIEWERS: To ensure that it meets institutional standards for quality and objectivity, this Proceedings of a Workshop—in Brief was reviewed by Hannabeth Franchino-Olsen, Gillings School of Public Health, University of North Carolina at Chapel Hill; Amy Leffler, Social Science Analyst, National Institute of Justice, U.S. Department of Justice; Mauricio Sadinle, Department of Statistical Science, Duke University; and Katrina B. Stone, CEO, Surveys & Behavior Analytics, LLC. Kirsten Sampson Snyder, National Academies of Sciences, Engineering, and Medicine, served as review coordinator.

SPONSORS: The workshop was supported by the Office of Women's Health, U.S. Department of Health and Human Services.

Suggested citation: National Academies of Sciences, Engineering, and Medicine. (2019). Estimating the Prevalence of Human Trafficking in the United States. Proceedings of a Workshop—in Brief. Washington, DC: The National Academies Press. doi: https://doi.org/10.17226/25550.

Division of Behavioral and Social Sciences and Education

Copyright 2019 by the National Academy of Sciences. All rights reserved.