Towards an efficiency interpretation of regulatory implementation lags

Regulatory agencies are often legally obliged to use a cost-benefit rule in revising environmental standards to reflect improvements in pollution-control techniques, but have considerable discretion over the timing of such revision. How should the agency use this discretion? Longer lags tend to encourage more intense R&D effort by the regulated industry itself whilst discouraging parallel effort by external developers. Optimal implementation lags are characterized. The analysis calls into question the conventional view that ''footdragging'' by agencies is necessarily evidence of incompetence or regulatory capture. More generally, whether or not subject to conscious manipulation by regulatory agencies, the delays routinely observed in implementation may enhance welfare.