This paper compares the effect on trainee earnings of an employment program that was run as a field experiment where participants were randomly assigned to treatment and control groups with the estimates that would have been produced by an econometrician. This comparison shows that many of the econometric procedures do not replicate the experimentally determined results, and it suggests that researchers should be aware of the potential for specification errors in other nonexperimental evaluations.

John C. Ham, Robert J. Lalonde, The Effect of Sample Selection and Initial Conditions in Duration Models: Evidence from Experimental Data on Training, Econometrica, Vol. 64, No. 1 (Jan., 1996), pp. 175-205

We exploit administrative data combining workers' earnings histories with information about their firms to estimate the magnitude and temporal pattern of displaced workers' earnings losses. We find that high-tenure workers separating from distressed firms suffer long-term losses averaging 25 percent per year. In addition, we find that displaced workers' losses: (i) begin mounting before their separations, (ii) depend only slightly on their age and sex, (iii) depend more on local labor-market conditions and their former industries, (iv) are not, however, limited to those in a few sectors, and (v) are large even for those who find new jobs in similar firms.

The authors address two questions using experimental data on disadvantaged women. First, what is the impact of being offered Job Training Partnership Act classroom training on the duration of unemployment and employment? Second, what is the effect of actually participating in this training on the length of such spells? Belonging to the treatment group shortens unemployment spells but has no effect on employment spells. Actually participating in training has a larger positive effect on the exit rate from unemployment than the effect of simply being a member of the treatment group. Ignoring the endogeneity of actual training in estimation substantially underestimates its effect.

We estimate the effect of endogenous training participation on transitions in and out of employment for disadvantaged women in the Job Training Partnership Act (JTPA) study. Decomposing the effect of training on employment into its effects on transitions in and out of employment has the potential to develop more effective programs. We also consider a potentially serious identification problem that arises when individuals do not undertake training immediately, and we propose a test to shed light on this problem. We find that this problem is not important in our context. JTPA classroom training substantially reduced unemployment durations, and thus it complements programs that increase employment durations.