The extent to which employee responses to productivity surveys assess what they are intended to assess has become a pivotal issue for employers and providers. Much work is now being devoted to the validity and reliability of these self-reports. Such issues will likely be resolved only over the long term. In the interim, the skepticism of business decision-makers who are unfamiliar with survey techniques needs to be addressed. This article taps the widespread acceptance that administrative adverse events have gained as indicators of productivity loss to address this issue. Joint analyses of adverse event measures and productivity self-reports on employees at International Truck and Engine Corporation are conducted to test 2 types of criterion validity: 1) concurrent validity; do prior/concurrent adverse events associate with self-reports as logic and common sense dictate? and 2) predictive validity; do self-reports distinguish the risk of subsequent adverse events? Self-reports are found to perform well in both sets of tests. The results are explored in light of: 1) concerns that users have with respect to how self-reports are now being applied, and 2) ways in which self-reports serve as a cornerstone for 3 articles that follow in this issue.