A Comparison of The CPS and NAWS Surveys of Agricultural Workers



Until 1988, the only continuing national survey of agricultural workers was the Census Bureau’s Current Population Survey (CPS). Several researchers contend that, because the CPS samples based on household location, it undersamples migratory and immigrant agricultural workers (especially undocumented workers) so that it provides a biased view of the agricultural labor market. As mandated by the Immigration Reform and Control Act, the U. S. Department of Labor is conducting the National Agricultural Workers Survey (NAWS) from 1988 to 1992. Because the NAWS sampling method is based on employment and not residence, it may avoid the biases to which the CPS may be prone.

We compare the CPS and NAWS samples to determine their differences and similarities. In addition to comparing the means and standard deviations of various important variables in the two surveys, we examine the implications of the two surveys for some standard econometric questions that these surveys are designed to answer.

In the first section, the two surveys are described. In the second section, the national means and standard deviations of several important variables are compared. In the third section, regional comparisons are used to determine if the two surveys differ more in certain regions than others. In the fourth section, equations for wages, hours, earnings, and the method of payment (piece rate vs. hourly) are estimated using multivariate regression and probit analyses and tests are conducted for differences in coefficients across the samples. In the last section, we draw conclusions and discuss the likely biases from relying on only one or the other of these samples. The policy implications are also analyzed.