Who should monitor job sick leave?

We use a large and unique administrative dataset from Italy, covering the period 2009-2014, to investigate opportunistic behavior (moral hazard) and the effectiveness of monitoring policies related to insurance against illness-related income losses. The analysis is based on the outcome of mandatory medical visits aimed at verifying the health status of employees during sickness spells. We find that employers are more effective than the public insurer in selecting sickness episodes to monitor. However, a reduction in the number and a better targeting of visits with the support of appropriate statistical tools may close the gap. We discuss the impact of using direct measures of health, such as the outcome of a medical visit, on the study of the determinants of opportunistic behavior and argue that simply looking at days of work lost, without appropriately controlling for health status, may lead to misleading conclusions if the goal is studying moral hazard.