Human Trafficking: New Global Estimates of Forced Labor and Modern Slavery


As part of long-standing congressional interest in global human trafficking, some Members have consistently sought greater fidelity in quantifying human trafficking's prevalence. In September, the International Labor Organization (ILO) and the advocacy organization Walk Free Foundation, in partnership with the International Organization of Migration (IOM), released a new report on the global prevalence of modern slavery (including forced marriage) and forced labor (including sex trafficking and government-imposed forced labor). The report estimated that 40.3 million people were victims of modern slavery in 2016—including 24.9 million people in forced labor and 15.4 million people in forced marriage (see Figure 1).

The estimate was based on a new methodology, derived from multiple data sources, household surveys, probabilistic modeling, and analytic reviews of secondary sources. Using 2012-2016 as the reference period for the study, it concluded that some 89 million people had experienced modern slavery in the past five years. The report additionally stressed that its estimates are conservative, noting the lack of data due to underreporting—particularly in conflict zones (estimates of child soldiers, for example, were not included).

Figure 1. ILO's 2017 Estimates of Modern Slavery and Forced Labor

Source: CRS based on the ILO and Walk Free Foundation, Global Estimates of Modern Slavery, 2017.

Global Estimates in Context

Estimates of human trafficking victims have varied widely and are a topic of ongoing debate. One of the earliest estimates prepared by the U.S. government in 1997 indicated that there might be some 700,000 victims worldwide. In 2005, ILO published its first global estimate of forced labor, which found that a minimum of 12.3 million people were in forced labor at any point during the time period between 1995 and 2004. The ILO revised its methodology to produce an updated global estimate in 2012, which found that 20.9 million people were in forced labor at any point during the time period between 2002 and 2011. Before the 2017 findings, the advocacy organization Free the Slaves had long estimated that some 27 million slaves worldwide. In 2016, the Walk Free Foundation estimated that 45.8 million people were held in slavery. Notwithstanding ongoing differences among various estimates, if the generally upward trend over the past two decades can be assumed to be correct, the latest figures may reinforce long-standing criticism of global efforts to identify victims and ultimately prosecute and convict their traffickers (see Figure 2). In 2016, governments around the world were able to officially identify 66,520 actual victims of human trafficking.

Figure 2. Human Trafficking: Prosecutions, Convictions, and Actual Victims

Source: CRS based on U.S. Department of State, Trafficking in Persons (TIP) Reports, 2010, p. 45, and 2017, p. 34.

Notes: According to the most recent TIP Report (2017), with data covering the years 2009-2016: "The above statistics are estimates derived from data provided by foreign governments and other sources and reviewed by the Department of State. Aggregate data fluctuates from one year to the next due to the hidden nature of trafficking crimes, dynamic global events, shifts in government efforts, and a lack of uniformity in national reporting structures. The numbers in parentheses are those of labor trafficking prosecutions, convictions, and victims identified."

Defining Modern Slavery

Definitional variances complicate understanding of prevalence. In its use of the umbrella term modern slavery, a term that is not comprehensively defined in international or U.S. law, the ILO report draws attention to a broader landscape of global human exploitation, including forced marriage. The State Department's 2010 Trafficking in Persons (TIP) Report clarified that "not all forced marriages result in cases of trafficking." Yet, its 2017 TIP Report appears to use the terms modern slavery and human trafficking often interchangeably. (See also CRS Report R44953, The State Department's Trafficking in Persons Report: Scope, Aid Restrictions, and Methodology.) Similarly, recent Congresses at times have conflated the terms modern slavery and human trafficking in hearings and human trafficking legislation. The international community, too, addresses forced labor, modern slavery, and human trafficking as interrelated, but not necessarily identical, global concerns. In 2015, for example, members of the United Nations agreed to a set of 17 Sustainable Development Goals and 169 targets, including target 8.7, which committed states to "take immediate and effective measure to eradicate forced labor, end modern slavery and human trafficking, and secure the prohibition and elimination of the worst forms of child labor, including recruitment and use of child soldiers."

Figure 3. Selected Definitions: International and U.S. Terms in Comparison

Source: CRS based on the 2000 U.N. Protocol to Prevent, Suppress and Punish Trafficking in Persons, Especially Women and Children; 1930 ILO Forced Labor Convention, including its 2014 Protocol; U.N. Office on Drugs and Crime, Global Report on Trafficking in Persons, 2016; U.S. Code; and

Implications for Congress

Whether U.S. anti-trafficking programs are intended to address the broader phenomenon of modern slavery or something more narrowly defined poses both legislative and oversight policy questions for Congress. Current bills in the House (H.R. 2200) and Senate (S. 1312) seek to reauthorize the Trafficking Victims Protection Act of 2000 (TVPA), whose authorizations for appropriations to eradicate severe forms of trafficking in persons, domestically and internationally, expired at the end of FY2017. The TVPA also contains the statutory provisions that require the State Department to prepare the annual TIP Report and rank countries on the basis of their efforts to eradicate human trafficking—provisions that several bills in the 115th Congress aim to modify. Some observers may seek clarification as to whether the TIP Report is intended to address modern slavery, generally, or the statutorily defined "severe forms of trafficking in persons" (see Figure 3). Congress may also conduct oversight of the State Department's new Program to End Modern Slavery, a recent initiative first authorized in the FY2017 National Defense Authorization Act (P.L. 114-328) and for which funding was appropriated in FY2016 (P.L. 114-113).