The study analyzes the attrition bias in estimating the average treatment effect of job training on wages. Endogenous and attrition biases were estimated using inverse probability weighting regression adjustment estimation (IPWRA, Wooldridge, 2007; 2010) and inverse probability weight. The results indicate, that both biases were overestimated. In comparison, however the former was initially higher, but the latter gradually increased. Finally, the Lee bounds (Lee, 2009) and IPWRA estimations were compared, and it was found that the former value was larger. A possible that Lee bounds were overestimated because they did not meet the assumption of randomized treatment.
