Our panel contained 173 California hospitals, of which 28 (16%) met our criteria for safety-net hospital (see ). On average, the safety-net hospitals had more beds and were more likely to be teaching institutions. All the city or county hospitals in our sample were considered to be safety-net hospitals. gives additional descriptive information about the hospitals by safety-net status.
Summary Statistics of Hospitals, 1998–2007
We plotted the average patient-to-nurse ratio over time to see whether there were differences between the safety-net and non-safety-net hospitals (). Safety-net and non-safety-net hospitals differed modestly in their staffing level before the legislation was passed in 1999. Nursing workload in terms of patient-to-nurse ratio decreased for both safety-net and non-safety-net hospitals, corresponding to the announcement of the final ratios by the California Department of Health Services in 2002 and continuing after the implementation in 2004.
Trends in Medical-Surgical Nurse Staffing among Safety-net and Non-safety-net Hospitals in California, 1998–2007
We also plotted nursing skill mix over the same period to examine differences in trends between the safety-net and non-safety-net hospitals (). Safety-net and non-safety-net hospitals had different initial levels of skill mix, with the safety-net hospitals having a significantly lower skill mix before the legislation was passed in 1999. On visual inspection and before any controls, it appears that skill mix increased for non-safety-net hospitals while remaining steady or increasing only slightly for safety-net hospitals. This contradicts concerns about skill mix reductions for safety-net hospitals. The gap between safety-net and non-safety-net hospitals, however, appears to have grown.
Trends in Medical-Surgical Nurse Skill Mix among Safety-net and Non-safety-net Hospitals in California, 1998–2007
When the California Department of Health Services released the final ratios in 2002, 45 percent of all the hospitals in our sample (39% of the safety-net and 46% of the non-safety-net hospitals) were staffed at a level that would have put them in compliance with the law (see ). The difference between safety-net and non-safety-net hospitals was not statistically significant (p = 0.50). In the period following the 2004 implementation of the mandate, 82 percent of safety-net hospitals and 92 percent of non-safety-net hospitals were staffed at a level consistent with compliance. The difference in the proportion of compliant safety-net hospitals versus compliant non-safety-net hospitals following implementation was not statistically significant (p = 0.09). Although a higher percentage of initially noncompliant non-safety-net hospitals became compliant (88%), compared with initially noncompliant safety-net hospitals (76%), the difference was not statistically significant. The average reduction in patient-to-nurse ratio was statistically significant across each group of hospitals (p < 0.001 for all groups except compliant safety-net hospitals, p = 0.03 for this group).
Medical-Surgical Patient-to-Nurse Ratio and Compliance Status in the Preimplementation and Postimplementation Periods
The fixed effects regression models estimate the effects of the legislation on staffing and skill mix for both safety-net and non-safety-net hospitals. We also included a term to indicate the degree to which each noncompliant hospital initially exceeded the mandated patient-to-nurse ratio, that is, the difference between the hospital’s initial patient-to-nurse ratio and the 5:1 patient-to-nurse ratio required by law after 2004. We specified our primary model identifying two time periods: preimplementation, representing the events before the mandate was enforced in 2004, and postimplementation, representing the period following 2004. A model specification with three time intervals (preannounce-ment, announcement, and postimplementation) demonstrated no significant effects from any announcement, suggesting that the announcement of the ratios in 2002 did not result in meaningful changes in staffing before the legislation’s implementation in 2004.
We found that the overall effect of implementation of the mandate across all hospitals resulted in nearly one fewer patient per nurse (−0.98 [p < 0.001]). We found significant differences in the effect on staffing based on safety-net status as well as the degree of initial noncompliance (see ). For initially compliant non-safety-net hospitals, the mandate had the effect of reducing patient-to-nurse ratios by 0.72 patients per nurse. The effect was smaller for initially compliant safety-net hospitals (a reduction of 0.46 patients per nurse). Although patient-to-nurse ratios fell in both safety-net and non-safety-net hospitals after the mandate, we found a statistically significant disparity in the magnitude of the change between safety-net and non-safety-net hospitals (0.27 patients per nurse, p = 0.02).
Effects of Implementation of California Staffing Mandate (AB 394) on Medical-Surgical Nurse Staffing and Skill Mix, 1998–2007
The greatest reductions in patient-to-nurse ratio following the implementation of the California mandate were for those hospitals that were initially understaffed to begin with—both safety net and non-safety net. For every additional patient per nurse above the 5:1 ratio in the preimplementation period, hospitals had an additional reduction of 0.62 patients per nurse. An alternative model to determine whether the change in staffing based on initial level of noncompliance was significantly different for safety-net and non-safety-net hospitals showed that the difference was not significant (0.14 patients per nurse, p = 0.2). Thus, our estimate of the effect of the degree of initial noncompliance is effectively an average of both safety-net and non-safety-net hospitals. shows the estimated changes in patient-to-nurse ratio following implementation for safety-net and non-safety-net hospitals based on their initial staffing levels.
Medical-Surgical Patient-to-Nurse Ratios before and after Reform in Safety-net and Non-safety-net Hospitals by Initial Staffing Level
The skill mix in all hospitals rose from the preimplementation period to the postimplementation period by a small but statistically significant amount (0.02 [p < 0.001]). The effect was significant and greatest for those non-safety-net hospitals (0.03 [p < 0.001]) that were initially adequately staffed at a level in compliance with the mandate. There was not a significant effect for safety-net hospitals (0.01 [p = 0.3]). The difference in the effect of implementation on skill mix for safety-net and non-safety-net hospitals was not statistically significant (−0.02 [p = 0.06]). There was no effect on skill mix based on the degree to which hospitals initially needed to increase their staffing in order to be in compliance.