This paper challenges the notion that on-the-job training investments are quantitatively important for workers' welfare and argues that on-the-job training may not increase lifetime income by more than 1 percent. I argue that it is very difficult to reconcile the slowdown in wage growth late in a worker's career with optimizing behavior unless the technology for learning on the job is such that it generates very low gains from training. The analysis is based on a nonparametric methodology for estimating the learning technology from wage profiles; the results are arrived at by comparing the lifetime income when the worker optimally invests in his human capital to the one where he does not make any investments.

We study optimal taxation when consumers have temptation and self-control problems. Embedding the class of preferences developed by Gul and Pesendorfer into a standard macroeconomic setting, we first prove, in a two-period model, that the optimal policy is to subsidize savings when consumers are tempted by “excessive” impatience. The savings subsidy improves welfare because it makes succumbing to temptation less attractive. We then study an economy with a long but finite horizon which nests, as a special case, the Phelps–Pollak–Laibson multiple-selves model (thereby providing guidance on how to evaluate welfare in this model). We prove that when period utility is logarithmic, the optimal savings subsidies increase over time for any finite horizon. Moreover, as the horizon grows large, the optimal policy prescribes a constant subsidy, in contrast to the well known Chamley–Judd result.