Research trends on human trafficking: a bibliometric analysis using Scopus database

Human trafficking (HT), or modern slavery, is an old problem [1]. However, in the past few decades, HT became a global concern [2, 3]. The most accepted definition of HT is presented by the Trafficking Protocol [4]. Human trafficking was addressed by several international agreements and conferences such as the International Agreement for the Suppression of White Slave Traffic (1904) [5], International Agreement for the Suppression of Traffic in Women and Children (1927) [6], the Trafficking Protocol (2000), and the Protocol against Smuggling of Migrants by Land, Sea, and Air (2000) [4]. The last two protocols recognized HT as a transnational crime rather than just human rights or migration issue [7]. Different countries used the UN Trafficking Protocol to develop criminal codes for HT. As of 2016, over 150 countries had criminal laws for HT [8]. In the USA, the Office to Monitor and Combat Trafficking in Persons releases an annual report (TIP Report) about international efforts to combat trafficking. The European Union adopted the Brussels Declaration on Preventing and Combating Trafficking in Human Beings which aimed to fight HT in Europe [9]. Other non-European and non-American countries developed their own national policies and protocols to criminalize and fight HT [10].

Sex trafficking is one of the most common forms of HT with more than half a million women being trafficked every year [6]. Forced labor, child labor, child soldiers, debt bondage, involuntary domestic servitude, and organ/tissue removal for transplantation are other common forms of HT [11]. Forced prostitution represents the highest percentage of HT victims with the majority being women from Eastern Europe, Central Asia, and North and South America [8, 12, 13]. In contrast, the majority of victims of forced labor are men from Africa, the Middle East, and Asia [8, 12]. International organizations distinguish between HT and smuggling. In smuggling, the actor takes part in the process while HT involves some deception or coercion [14]. Unlike HT, migration and smuggling are less often involved with a criminal organization [14].

Human trafficking has a global dimension despite that trafficking could occur within the same country [8]. Human trafficking affects people of all races, religions, social class, and education. It often results in mental health disorders and life-threatening infections [8, 15‐20]. For example, a study of 207 trafficked women from 14 countries reported that 95% of women had experienced physical and/or sexual violence [21]. A study on trafficked Nepalese girls and women found that 23% of them tested positive for HIV [22]. Despite its negative social, health, and legal consequences, HT is a growing business for criminal organizations [21, 23]. Poverty, social injustice, disasters, substance abuse, family breakdown, and homelessness are major push factors for victims [24‐26]. Globalization has created a larger gap between developing and developed countries with poverty and marginalization being major push factors for victims [1].

The International Labor Organization (ILO) reported 12.3 million trafficking victims in 2005, 21 million victims in 2012, and 40.3 million victims in 2016 [27]. The 2016 report of the ILO estimated that 40.3 million people in modern slavery, including 24.9 in forced labor and 15.4 million in the forced marriage [28]. Out of the 24.9 million people trapped in forced labor, 16 million people in the private sector such as domestic work, construction or agriculture; 4.8 million persons in forced sexual exploitation, and 4 million persons in forced labor imposed by state authorities [27]. The ILO considers the Asia-Pacific region to have the largest number of victims of HT followed by Africa and Latin America [28]. It was estimated that over 40% of trafficked victims were detected in their own countries and that 71% of the trafficked victims were women while 28% were children [8].

Bibliometric analysis is a research method used to shed light on research activity [29‐31]. It differs from systematic reviews, which aim to answer a specific research question based on a selected group of articles [32, 33]. It also differs from scoping reviews, which aim to identify the nature and extent of research evidence [34, 35]. Bibliometric studies were carried out to provide a snapshot of national and international contribution to literature [36] and to advance information and science [37]. Bibliometric indicators assess national and international efforts carried out to achieve a particular goal. Several bibliometric studies on migrants and refugees have been published [38‐40]. However, none was carried out on HT. Therefore, the aim of this study was to analyze published literature on HT. Such a study will shed light on the global research activity and discussed themes in literature on HT. Bibliometric analysis may be useful for health authorities and UN agencies interested in mapping and identifying research gaps within the HT research landscape, which is important for advancing an evidence-informed research agenda. Findings of a bibliometric analysis are difficult to obtain by other research methods such as systematic or scoping reviews. For example, a recent systematic review of research methods on HT and health concluded that despite the presence of various quantitative and qualitative data collection and analysis methods, the implemented methodological approaches have limitations that affect what is known about HT and health [41]. Most available literature on HT is based on emotional stories rather than on empirical research [42]. Bibliometric analysis would give an accurate quantitative analysis of literature on HT that would serve as a basis for future studies. The findings of a bibliometric study on HT will shed light on the evolution, volume, and scope of research on HT and will help identify countries and regions lagging behind in this field [5]. A bibliometric analysis of literature on HT will also give detailed information on the number of publication on each type of HT and therefore a direct academic and research effort as well as funding towards less-researched types of HT.

The current study is the first to assess research activity in the field of HT. The current study showed that health aspects of HT were under-represented compared to criminal, legal, and social aspects of HT. Similarly, research on labor trafficking was under-represented compared to sex trafficking and exploitation. The literature on HT represents the agendas of destination countries with limited contribution of countries in Asia, Latin America, Africa, the Middle East, and Eastern European. Future research plans should shed light on trafficking for non-sexual purposes. Furthermore, research networks need to be strengthened by including scholar from source and destination countries to investigate health conditions of trafficking survivors or exploited migrants. Greater investments in international research collaborations and research networks should be encouraged to help prioritize research on HT in various world regions.