• Sample Information
• Information on Continuing Education and Job Training

DATA

To understand the changes in the patterns and value of training during the past three decades, I make use of data from the National Longitudinal Surveys from 1966 to 1981 and the comparable National Longitudinal Survey of the Labor Market Experiences of Youth from 1979 to 1994 (NLS, collectively). The NLS offers an excellent source of information for the study of training. For each cohort, detailed information is available about work experience and about the amount and types of education and training workers engaged in after completing their formal education. For example, workers were regularly asked to identify the types and duration of any continuing education or training in which they engaged between interviews. Moreover, these data provide information about where workers received their additional training (e.g., at a community college, vocational institute, or at their places of employment).

Sample Information

For my purposes, I examined the experiences of a sample of young men surveyed annually as part of NLS's original cohort of young men (NLS-OC). Beginning in 1966, the NLS-OC interviewed 5,225 men between the ages of 14 and 24. These men were interviewed in person or by telephone during all but four years until 1981, when their ages ranged from 28 to 39.

I compared the experiences of young men from this original cohort to the experiences of young men beginning their careers in the late 1970s and early 1980s. I drew this sample of younger men from the National Longitudinal Survey of the Labor Market Experiences of Youth (NLSY). Beginning in 1979, the NLSY surveyed 12,686 men and women whose ages ranged from 14 to 21. These men and women have been interviewed annually, in person or by telephone, each year since then.

Drawing on the NLS-OC and NLSY, I was able to examine the patterns of training in which two comparable cohorts engaged during the early years of their careers. Moreover, these data allowed me to assess the importance of such training on the earnings of each cohort.

I restricted my focus for this paper to a comparably aged group of white men from each sample. I limited my analysis to men because dramatic changes in rates of labor force participation among women between the 1960s and early 1990s confound any inferences that can be drawn about the relationship between training and the earnings of women between these cohorts.

I restricted my analysis to whites because of a very high rate of sample attrition for blacks in the NLS-OC. Overall, the NLS-OC had a retention rate of 64.9% by the final interview in 1981. This is lower than the 89.3% retention rate for the NLSY sample by the 1994 survey. While the overall rate of attrition was relatively high among the first cohort, the rate at which black respondents failed to be interviewed from year to year was especially bad. As an illustration, for the NLS-OC, 73% of white respondents were interviewed in at least nine of the twelve years during which the cohort was interviewed. Among the NLSY cohort, 82% of white respondents completed at least nine interviews. For blacks, however, completion rates were substantially different between cohorts. Among the NLS-OC cohort, only 56% of respondents completed nine interviews. This compares poorly to the 89% of black respondents completing at least nine interviews during the NLSY survey. Because of these relatively stark differences in rates of non-interviews for blacks between cohorts, I chose to focus on white workers, for whom interview rates are more comparable from one cohort to the next.

I limited my analysis of the NLSY data to the cross-sectional sample designed to be representative of the population 14 to 21 years old in 1979. The NLSY also included a number of supplemental samples designed to collect detailed information on populations which otherwise might be represented in too small numbers to explore certain research questions. These included oversamples of poor whites and of young people in the military. The NLS-OC sample included no such oversampling of poor youths or of those in the military, instead drawing a sample designed to be nationally representative of the population 14-24 years old in 1966. In order to ensure comparability, I use only those portions of the NLS-OC and NLSY samples designed to be nationally representative.

Furthermore, because the age range of the NLS-OC cohort is broader than the NLSY cohort, I dropped sample members of a certain age from the NLS-OC cohort. I ended up with samples that were comparably aged (28 to 36 years old) in the final years which I am considering (1981 for the NLS-OC and 1994 for the NLSY). In Table 1, I present descriptive statistics on the NLS-OC and NLSY samples in 1981 and 1994, respectively.

Table 1
Sample Means, NLS-OC and NLSY Cohorts

Two important differences in the characteristics of the cohorts are notable. First, the second cohort is less educated than the first. Clearly, the educational attainment of the general population has been rising during the twentieth century; however, the flood of highly educated young people into the labor market as the baby boom left college during the 1970s bid down relative wages for more educated workers, especially among the young. Subsequently, the rate of college entrance among high school graduates in the 1980s fell as college became less appealing. As a result, during a time of rising general levels of education, educational attainment for the cohort of men leaving high school in the late 1970s and early 1980s fell compared to their immediate predecessors (U.S. Census Bureau, 1996).

The second important difference between cohorts is the lower rate at which members of the second cohort served in the armed forces. A full 39.9% of young men in the first cohort report serving in the armed forces by 1981 compared to only 11.6% of the second cohort by 1993. This difference is an artifact of the Vietnam War. [1] The workers I examined from the NLS-OC data were just coming out of high school during the peak years of Vietnam-era conscription. Indeed, 14% of the men in the first cohort reported having been in combat. I attempt to account for these differences between cohorts by including controls for veteran status in all models estimated below. Furthermore, I included a dummy variable set to one for all members of the original cohort who report having served in combat. [2] To the extent there is any larger cohort effect due to the Vietnam War, these controls may be inadequate, and the reader is urged to interpret the results in the context of his or her own assessment of the impact of such an event on the learning and earnings of the respective cohorts.

Information on Continuing Education and Job Training

To collect information on the continuing education and job training in which the young men in each of the samples have engaged, I make use of their responses during the full series of interviews. During the course of the NLS-OC, respondents were routinely asked about the educational programs or training courses they had taken other than their regular schooling. Respondents were informed that such training could have been taken either at work or elsewhere. Similarly, respondents to the NLSY surveys were routinely asked about the training they received other than regular schooling. In each case, respondents were asked only about the training they had engaged in since the last interview (with the exception of the first interview administered).

Both the NLS-OC and NLSY provide rich information about the training in which respondents engaged. This information includes the source of training, such as vocational-technical and community colleges; training provided at the place of work either by the employer or by an outside trainer; and government-sponsored training. [3] Respondents are also asked other details about their training such as its duration and frequency. From this information, I was able to construct a detailed history of individuals' participation in training, including the type, frequency, and duration of the training in which they engaged over the thirteen-year period prior to interview. [4] More details about the questions asked of respondents in each sample are provided in Appendix 1.

While both the NLS-OC and the NLSY provide rich sources of data about the amount and types of training undertaken by young men in each of these cohorts, there is an important difference between these two surveys. While the NLS-OC contains a series of questions about training that is largely consistent over time, sample members were not interviewed every year. The NLSY, however, did attempt to interview its sample members annually. This difference in interview intervals can affect the inference drawn about trends in the incidence of training.

Each survey asked respondents about the training in which they engaged since the date of their last interview. For four of the ten NLS-OC interview years used here, the training questions asked respondents to describe the training in which they engaged over the preceding two-year period. [5] During the other six NLS-OC interview years, the training questions referred to training during the one year preceding the interview. For the NLSY, however, in only one interview year (1988) were respondents asked about training over the preceding period of at least two years. In all other years, the relevant period was only approximately one year in length.

These differences in interviewing patterns means that studying trends in training between cohorts requires that I had to rely disproportionately on the original cohort's ability to recall training which occurred over longer periods. There is no fully satisfying way to determine the effect of these different recall periods on the amount of training reported by each cohort. For both cohorts, more training was reported at interviews following a two-year interval since the last interview, and for both cohorts the incremental increases in reported training associated with the two-year interval are very similar. [6] Because of its length, we would expect an increase in reported training following a two-year interview interval; however, I am unable to determine whether the observed increase sufficiently captures all of the training respondents engaged in over the longer interview interval, or if training is more likely forgotten if it occurred sometime in the past two years, rather than the past one year.

If there is any substantial additional inability to recall whether or not an individual participated in training during the past two years, rather than the past one year, I will likely under-count the training in which the original cohort engaged. As we will see, however, this potential under-counting of training among the original cohort does not affect the principal conclusions about trends in training. That is, I observed no real increase in training incidence consistent with a growing demand for skilled workers. Any differential under-counting would only reinforce this conclusion.

[1] These estimates agree with U.S. Department of Veterans Affairs (USDVA) reports of the population of veterans in comparable cohorts. Based on USDVA's annual Veteran Population in 1995, about 39% of men in the cohort from whom the NLS-OC data are drawn were veterans. Among men in the same cohort as the NLSY sample, 12% were veterans.

[2] One might expect combat to negatively affect earnings, either due to any lingering effects on productivity or because the measure of combat might pick up an important heterogeneity associated with the manner in which members of the armed forces are assigned to combat duty. While the coefficient on this variable is routinely negative in earnings models, it is never significant.

[3] The primary battery of questions about training in the NLSY did not include information on government-sponsored training between 1979 and 1986. Instead, another battery of questions was administered to collect information on participation in government training programs.

[4] I restricted my analysis to civilian training. As a result, I examined training which respondents reported was neither provided by the military, nor occurred while on active duty.

[5] For both the NLS-OC and NLSY data, "since the last interview" can exceed the one- or two-year survey interval because of non-interviews in any year.

[6] I analyzed the effect of interval length on the proportion of each sample reporting training by regressing the proportion reporting training on a time trend, and a measure of the time since the last cohort interview. For both cohorts, a two-year interview interval was associated with an additional 5% of the sample reporting training, over and above the trend.