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Study: Illegal Child Labor in the United States
Sponsored by The Associated Press

II. Data Sources and Limitations

The main data source used in this study is the Current Population Survey (CPS), which is a survey of roughly 60,000 households done each month by the Census Bureau and the Bureau of Labor Statistics. The CPS currently asks employment questions for those age 15 and older, including hours and occupation questions that can be used to determine whether the minors appear to be working in violation of federal and state laws. Because there are only about 6000 15- to 17-year-olds in one month's sample, this study combines data from 33 monthly surveys covering January 1995 to September 1997 to create a large sample of over 186,000 15- to 17-year-olds.{1} The standard monthly survey measures current employment, allowing estimates of who may be illegally employed in an average week. In order to estimate the number who are illegally employed at some point during a year, estimates are also made using the March 1997 supplement asking about employment throughout 1996.

Estimates of illegal employment from the CPS are primarily based on questions about occupation and usual hours worked. Federal law restricts work in 17 hazardous occupations for those under age 18, and further restricts the type and location of work for those under 16. These restrictions were matched to CPS occupation codes (with the restrictions and matched codes listed in Appendix A) to determine which individuals appear to be engaged in illegal work. Federal law also restricts 14- and 15-year-olds to no more than 18 hours of work during a school week and 40 hours of work during a non-school week; therefore those reporting a job during school months (January-May and September-December) are coded as working illegally if their usual hours worked exceeds 18, and those reporting a job during summer months (June-August) are coded as working illegally if their usual hours worked exceeds 40. Because the FLSA does not apply to self-employment, and hours restrictions do not apply (although occupation restrictions do apply) to jobs in a family business, adjustments are made to ensure that these jobs are not counted as illegal work.{2} The FLSA also does not cover most small businesses not engaged in interstate commerce, which employ about one-eighth of all workers, but those workers are generally covered by state laws (many of which apply federal or higher standards). For this study, those state restrictions (obtained from state Web sites and Research Institute of America, 1996) are coded and applied to youths in those states, so that the numbers presented here include any minors working in violation of state or federal child labor laws.{3}

To obtain estimates of illegal employment for those under 15, an imputation is made based on several other datasets. Legal and illegal employment of 14-year-olds is imputed based on 1980s data from the CPS (since employment questions were asked of 14-year-olds until 1989), and from two National Longitudinal Survey (NLS) datasets - the NLS-Youth and NLS-Adolescent Health datasets. The employment of children younger than 14 is imputed using the NLS-Adolescent Health dataset and several sources on work-related injuries and deaths broken down by age.

There are several limitations in using the CPS and other survey data to detect illegal employment. The first is that survey respondents are unlikely to report to an interviewer any behavior that they know to be illegal. While it is safe to say that most people are aware that child labor laws exist, the extent of knowledge about the provisions of those laws is unclear. Employers are held responsible for obeying child labor laws, but minors and parents are generally not responsible and therefore under no obligation to be aware of the laws. As will be seen, a large number of survey respondents report employment that clearly conflicts with child labor laws, which may serve as an indication that many minors and parents are not aware of the laws. To the extent, however, that respondents underreport employment known to be illegal, the estimates reported here will undercount the illegal employment of minors. Some adjustment is made for this in the case of sweatshop employment by including an estimate of children working illegally in sweatshops.

A second important limitation of survey data is that existing surveys do not contain enough detailed data to clearly establish in many cases whether employment is legal or illegal. None of the surveys used here have data on the specific hours worked during a day, which would help determine whether some children are working during school hours or late into the night (both prohibited by child labor laws). The coding of occupational categories can also leave room for doubt over whether the actual work being done is proscribed for someone of that age. The CPS uses over 500 codes for occupation, some of which clearly establish illegal employment for those under age 18 (such as an occupation in which one drives a motor vehicle most of the time). Other occupational codes, however, leave room for some ambiguity over whether the activity is proscribed (such as an occupation that may or may not involve power-driven machines, or work in a manufacturing area). For this study employment is identified as illegal when the occupational description conflicts with federal or state laws for someone of that age. It is not clear whether any ambiguities in occupational coding and the lack of detail on job descriptions will generally lead to an understatement or overstatement of illegal work performed by minors; the figures are probably more likely, however, to be understated since work was coded as illegal only where there was an obvious conflict with laws. Balancing this understatement is that some youths may be legally doing hazardous work under an apprenticeship program, for which insufficient information is available to adjust the numbers.{4}

Finally, a limitation of survey data is the potential for measurement error, both from respondent reports and interviewer coding. To the extent that measurement error exists, it will not necessarily understate or overstate the extent of illegal employment. Some respondents may mistakenly report that a 15-year-old works 20 hours per week during a school week when the correct number is 15, but just as many errors might go in the opposite direction. One source of potential measurement error in the CPS comes from the fact that over 90% of the reports on the employment of 15- to 17-year-olds do not come from the adolescents but from parents or others in the house. The results, however, do not differ markedly when comparing self-reported vs. other-reported data, so this is unlikely to seriously bias the overall numbers.


{1} To account for unequal representation of months, the monthly data were re-weighted to give each month of the year equal weight.

{2} The occupation codes of those who reported self-employment were evaluated, and several were recoded as being employees (e.g., waiters/waitresses). Those who work in a family business or farm are not subject to hours restrictions; one can easily identify those who did unpaid labor in a family business, but not those who work for pay in a family business or farm. In this study, 15-year-olds from a household with a business or farm were more likely than others to work apparently excessive hours for a private employer, but many may have been working for a family business. To adjust for possible upward bias from incorrectly coding many of these people as working illegally, the data were re-weighted so that the percentage working excessive hours for a private business was identical among those with and without a business or farm in the household.

{3} A few percent work in businesses not covered by federal or state law, so that the procedure here will somewhat overstate those working in violation of child labor laws. This is likely to be more than balanced, however, by several sources of understatement to be addressed. {4} Numbers are available on total youths enrolled in apprenticeship programs, but breakdowns by hazardous occupation could not be located.


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