Health policy reforms in New Zealand during the 1990s impacted on hospital operations, on the nursing workforce, and on patients. This study analyses changes in rates of 20 adverse patient outcomes that are potentially sensitive to nursing (OPSNs) before (1989-1993), during (1993-2000), and after (2000-2006) the policy reforms, using all New Zealand public hospital inpatient discharge data for this period. Comparisons of changes in mean annual rates across periods revealed the expected trajectory of acceleration during the reform period relative to the prereform period, and a subsequent deceleration in the postreform period. This S-shaped pattern was clearly evident in 16 of the 20 OPSNs, and partially evident in the remaining 4. These results are interpreted as evidence that the 1990s policy reforms inspired by managerialism had deleterious effects on patient outcomes, and that these effects coincided with changes in nursing resources and the work environment.