Zhang, Sheldon. Looking for a Hidden Population: Trafficking of Migrant Laborers in San Diego County. San Diego: San Diego State University Press, 2012.

Zhang, Sheldon. Looking for a Hidden Population: Trafficking of Migrant Laborers in San Diego County. San Diego: San Diego State University Press, 2012.

• Many US businesses benefit from illegal or unregulated labor forces. Agriculture, landscaping and gardening, construction, hospitality, food processing, and domestic and custodial services all employ disproportionate amounts of illegal workers (25).
• Both the US government and foreign bodies, like the UN and ILO, recognize the scope of the problem. This is not, however, a comprehensive or informed estimated about the number of illegal workers or their working conditions. This undermines efforts to address the problem (26, 31, 37). 
• The author undertakes a limited survey of illegal workers in San Diego county. This provides a glimpse into the situation until a national survey can be undertaken (26-27).
• Free the Slaves, an NGO, estimated that slavery in the USA is most concentrated in California, Florida, Texas, and New York, especially areas with large immigrant populations (28). US was estimated to have had approximately 11.2 million illegal immigrants in 2011, with around 58% being Mexican and 23% being from other Latin American countries. California is believed to be host to a quarter of all illegal immigrants, making up around 8% of the state's population (82-83).
• The growth of slavery in recent decades is due to population growth in poor countries, which increases competition for work and lowers labor costs, and rapid industrialization and globalization that destroys old economies and forces adaptation (27).
• Slavery is most common in economic sectors were labor costs constitute the majority of expenditure, like agriculture and construction. Slaves tend to be used for the most labor-intensive work (28).
• Contemporary [2012] estimates suggest that tens of millions of people are enslaved worldwide, with the absolute majority enslaved in India, Bangladesh, Pakistan, and Nepal. Upwards of 80% are estimated to be enslaved by businesses or individuals, with the rest being enslaved by governments or rebel groups. The majority of slaves do forced labor, with between 10% and 20% being forced into sex work (28-29).
• Governments have concentrated most of their resources, and academics and journalist most of their attention, on sex slavery, with much less effort going into abolishing forced labor in other sectors. This has even led to a popular misconception that the majority of slaves are trafficked for sex work (29-30).
• There is not an internationally recognized definition of labor trafficking, which impedes international cooperation to tackle the issue. Some countries do not recognize slavery for the purpose of forced labor as a crime, while others simply list it as a form of illegal immigration (33-34).
• In 2000, the UN did issue the Protocol to Prevent, Suppress, and Punish Trafficking in Persons [the Palermo Convention] that defined labor trafficking as extracting labor for economic gain by threat or fraud (34).
• This definition does not, however, lay out how to prosecute those involved in human trafficking through smuggling, transport, storage, or recruitment, whose specific crimes do not fall under this definition (34).
• The US definition of human trafficking is in the Victims of Trafficking and Violence Protection Act, passed 2000, which defines sex trafficking and labor trafficking as the recruitment, harboring, transportation, provision or obtaining of a person for sex or labor, respectively, through coercion, force, or fraud (34-35).
• The same vulnerability that allows illegal immigrants to be enslaved and exploited also makes them unlike to participate in normal modes of survey or collecting information. Participating in these activities places them in danger and high levels of trust are needed to encourage their participation (39). This vulnerability also means that anti-slavery operations are more difficult to conduct (89).
• The author outlines the methodology of the study from page 39 to page 52, and from page 54 to page 62. 
• San Diego has, following deindustrialization in the 1980s, shifted to a major agricultural economy. The agricultural sector is widely believed to be heavily dependent on immigrant and slave labor. During the 1990s, approximately 90% of all agricultural workers were immigrants, of which an unknown proportion were enslaved (52-53).
• San Diego's position on the Mexican-American border and the fact that half of the city area is rural have made it a popular site for illegal immigration into the USA. This has intensified after Operation Gatekeeper in 1994 initiated an era of stronger border controls elsewhere. San Diego's proximity to the border means that migrants can cross back into the US more quickly if they are deported (52-53).
• The author found that the illegal immigrant population in San Diego is overwhelmingly Mexican and has a fairly even gender distribution. The average illegal immigrant is 33 years old, with around 45% of the population being under 30 years old. Only 12% have graduated high school and over 20% have no formal education (63). There is a roughly even split between married and single migrants, but 70% have at least one child (63-64). Over 90% spoke native Spanish, with the minority speaking Mixteco, Zapoteco, Nahualt, or other Native American languages. The community was roughly evenly split into groups that spoke no English, those who knew basic sentences, those with limited command, and fluent speakers. Around one-third of illegal immigrants had lived in San Diego for over 11 years. Over 90% of migrants either rent property or live with family, but around 6% are either homeless or live in canyons. Most of the illegal immigrants work in low-skill fields. Custodial work, agriculture, and food processing each employ roughly one-fifth of the population, with another 12% working in construction (64).
• The author suggests that Mexicans may have been overrepresented in the sample because tightly-knit immigrant groups may not spread outside of national lines. However, the author does not know of other major Latino communities in the city besides Mexicans and Americans (63, 96-97).
• There is a divide between the primarily-agricultural north of San Diego county and the service economy-oriented south. These separate communities are reflected in the demographic data, with the northern part having more men, a lower average rate of education, and much less English language ability, whereas the south has more women, a higher average education, and much more English language ability (64-65, 76).
• Approximately 58% of illegal immigrants in the survey experienced some form of exploitation during the trafficking process or while working in the US. Approximately 31% are or had previously been enslaved in San Diego county (66-67).
• Only 6% had been enslaved by traffickers prior to arriving in the US, although 23% were abused or exploited by traffickers during transit (67-68). 85% has hired smugglers to help them get into the US, with this rate rising to 94% in the northern part of San Diego compared to 78% in the south (71-72).
• Approximately half of all illegal immigrants had been abused or exploited by their employer, and 28% had been enslaved. There was no significant different between the level of abuse experienced by free and enslaved laborers. Enslaved migrants had been deceived around 30% of the time, while another 22% had been threatened with basic needs being restricted and 15% had been threatened with physical violence (68).
• Abuse was more prominent in the southern part of San Diego county than in north, the difference between a 60% rate of abuse versus 36%. Slavery was also more common in the south, with 37% of illegal immigrants in the south being enslaved compared to only 17% in the north (70-71). This is likely because of the low rates of slavery and abuse in the agricultural sector that dominates the northern part of San Diego county (78).
• Slavery and workplace abuse were least prominent in the agricultural sector and most common in janitorial work and landscaping (71). Only 27% of agricultural laborers were abused and under 16% were enslaved. Janitorial and custodial work, landscaping, and food processing all had high rates of abuse and slavery, with roughly 59% being abused and 37% being enslaved (72-73).
• Physical abuse or threats of physical abuse were most common against slaves in food processing, janitorial work, and landscaping, with around 20% being threatened this way. Between 20% and 30% were threatened with restriction or deprivation in these sectors and around 40% had been enslaved through deception in food processing and construction. Slavery is least common in agriculture, with only around 10% of illegal immigrants reporting being enslaved through force, threats of restriction of basic goods, or deception each (74-75).
• The most common form of workplace abuse against illegal immigrants is denial of pay or underpayment. Less serious forms of abuse, like threats of deportation, are more common that serious physical or sexual abuse (76).
• Greater financial need is directly connected to a higher likelihood of abuse or enslavement. Those in the greatest need are most likely to accept risky offers that leave them open to abuse or trafficking (78-79).
• Slavery and workforce abuse are both widespread in San Diego county, with over 30% of illegal immigrants being enslaved and 55% being subject to some form of abuse by their employer (80). Slavery and abuse were least common in the agricultural sector and most common in the food processing and construction industries (80).
• Abuse and slavery appear to be uncommon among farm workers in San Diego because the farm laborer community is tightly-knit, well established, and drawn mainly from central Mexico, particularly Oaxaca. Even new migrants know the standard pay and treatment to expect, making them more difficult to exploit (81).
• Based on the estimated number of illegal immigrants in the US and the findings of exploitation among illegal immigrants in San Diego county, the author estimates that of the roughly 200,000 illegal immigrants in San Diego county, around 40,000 are enslaved (84-85).
• If these rates reflect the state-wide or national levels of enslavement -- the author does not suggest that they do (86, 95) -- then they would be around 500,000 slaves in California and 2.5 million slaves in the US as a whole (85).
• Disregard for US labor law is widespread in certain industries, with the minority of businesses complying with legal standards in some cases. This general disregard for labor law may indicate that abuse of workers or slavery may be similarly widespread elsewhere (87-88).
• Weak enforcement mechanisms and low penalties for violation of US law labor are the main causes of labor law violations (88).
• Bussiness owners will only comply with regulations, including those against slavery, if enforcement is strict and there are strong penalties. Neither of these is currently true, and slavers are unlikely to have be held accountable for their crimes (90).
• Public perceptions of labor trafficking in the US makes it difficult to effectively mobilize support for ending slavery in the sector. Most farm owners using slave labor are viewed as normal members of the community, whereas enslaved and abuse illegal immigrants are primarily viewed as criminals rather than victims (89-90).
• This could be solved by granting more legal protections to illegal immigrants, but this is unlikely considering the general dislike for illegal immigration (90). 
• Few slavery cases are brought to the attention of federal authorities, so the government needs to prosecute these cases to the fullest possible extent and invite publicity to send out the message that this is unacceptable and will be punished (91).
• Efforts by federal and state governments to crack down on slavery have definitely increased in the 2000s, with the passage of the Victims of Trafficking and Violence Protection Act in 2000 and the establishment of a special taskforce by the Department of Justice in 2007, prompting several similar units at the state level (91).
• The response at the state level overwhelmingly focused on sex trafficking, however. Most state law enforcement agencies have never prosecuted a labor trafficking case and many do not recognize it as a crime. More assistance to states is needed from the federal government (91-92).
• Cooperation between federal, state, and local law enforcement should recognize the high levels of distrust among illegal immigrant communities due to US immigration policies. The US should try to increase trust be prosecuting slavers rather than trafficked illegal immigrants (92-93).
• Public information campaigns, in both English and Spanish, can help increase awareness of human trafficking. This campaign will not deter slavers, but it will inform victims and communities that human trafficking is a crime and that recourse to law enforcement exists (93-94).