Nurse staffing levels: impact of organizational characteristics and registered nurse supply.

In 2002, the Bureau of Health Professions at the Health Resources and Services Administration released a report on the supply of, demand for, and shortages of registered nurses (RNs) (Biviano et al. 2004). The report, based on data from state licensure boards, census data, labor statistics, National League for Nursing annual surveys, and the National Sample Survey of Registered Nurses, found a 6 percent shortage in the supply of RNs. The report further predicted the shortage would increase to 12 percent by 2010 and to 20 percent by 2020. However, the shortage was not spread evenly across the states; rather, in 2000 no shortage existed in 21 states while the study identified shortages ranging from 3.5 to 17 percent in the other 29 states. Nurses perceive a shortage in the practice setting and report that the quality of care provided is declining as a result. A majority of the respondents in a national survey of 4,108 randomly selected nurses working in inpatient units reported that the shortage of nurses has been a major problem, affecting the time nurses have to devote to each of their patients (89 percent), the quality of patient care provided by nurses (77 percent), the ability of nurses to maintain patient safety (64 percent), and the early detection of patient complications by nurses (64 percent) (NurseWeek/AONE 2002). Since Aiken's landmark study published in 1994, evidence has been building that higher nurse staffing levels in hospitals are associated with better quality of patient care (Aiken, Smith, and Lake 1994; Blegen, Goode, and Reed 1998; Blegen and Vaughn 1998; Kovner and Gergen 1998; Aiken et al. 2002; Kovner et al. 2002; Needleman et al. 2002; Unruh 2003a, b; Person et al. 2004; Needleman et al. 2006). Discussions of these research results uniformly include concerns about the impact of the nursing shortage on the quality of care and the safety of patients; however, only one research report in the last 15 years addressed the direct impact of the shortage on hospital staffing (Grumbach et al. 2001). Decisions about staffing levels in hospitals must balance personnel costs with the intensity of care required by the population of patients served by each hospital. The acuity of the patients, standards for staffing set by experts and professional groups, reimbursement rates, and the orientation of the hospital or hospital corporation (for-profit, not-for-profit) influence this balance. In addition, market and other environmental factors, such as the supply of nurses, influence the decisions about staffing and staffing standards. Little study has been done on the actual influence of these factors on staffing levels. This study is part of a larger project examining staffing and patient outcomes in a national random sample of hospitals. The purpose of this analysis was to assess the impact of nurse supply in the geographic areas surrounding the hospitals on patient care unit staffing levels, while taking into account hospital factors that influence nurse staffing levels. We analyzed several measures of patient care unit staffing in relation to the supply of RNs, the type of unit (intensive care, stepdown/telemetry, medical/surgical), unit size, and hospital complexity (size, technology, teaching status, patient case mix). Nurse staffing measures included RN hours per patient day (Hppd), LPN Hppd, Total Hppd, RN mix (proportion of total hours provided by RNs), and licensed mix (proportion provided by RNs and LPNs). Two research questions were posed: Controlling for patient care unit type, unit size, and hospital complexity, what is the impact of the supply of RNs in the surrounding geographic area on hospital nurse staffing? What are the relationships between the supply of RNs and hospital RN vacancy rate, turnover rates, overtime hours, and the use of agency or traveler nurses? While there has been a great deal of interest in the effect of nurse staffing levels on the quality of care in hospitals, there has been much less interest in determining the factors that affect the nurse staffing levels other than documenting the changes during the health care crisis of the past 15 years (Aiken, Sochalski, and Anderson 1996; Anderson and Kohn 1996; Spetz 1998; Buerhaus and Staiger 1999; Bond and Raehl 2000; Unruh 2002). Recent work has established that the supply of nurses is not meeting the demand for nurses and that this shortage will worsen in the decades to come (U.S. DHHS 2002). While the conclusion that a local shortage of nurses will decrease the level of RN staffing in hospitals is logical, there is little evidence actually linking them or estimating the magnitude of the effect. The determinants of RN staffing levels in hospitals have been examined directly or indirectly while investigating other questions. The type of patient care unit makes the biggest difference, with higher staffing levels on units with more acutely ill patients (Blegen, Goode, and Reed 1998; Blegen and Vaughn 1998; Brewer and Frazier 1998; Hodge et al. 2004). Unit level staffing is high in teaching hospitals (Mark, Salyer, and Wan 2000; Hodge et al. 2004; Seago, Spetz, and Mitchell 2004); hospitals with more acutely ill patients (Brewer and Frazier 1998; Mark, Salyer, and Wan 2000); and hospitals in rural areas (Brewer and Frazier 1998; Hodge et al. 2004). Not-for-profit hospitals and those located in areas with more competition and higher managed care penetration have higher staffing levels (Mark, Salyer, and Wan 2000; Seago, Spetz, and Mitchell 2004). Three studies examined hospital-level RN staffing using American Hospital Association (AHA) data from the early 1980s. Hospitals with higher staffing were located in areas with a more competitive market (Robinson 1988); were larger (Becker and Foster 1988; Bloom, Alexander, and Nuchols 1997); were private (Becker and Foster 1988); were located in urban areas (Bloom, Alexander, and Nuchols 1997); and were teaching hospitals (Bloom, Alexander, and Nuchols 1997). Bloom and colleagues added an RN supply factor to their model (ratio of number of RNs in the county to hospital beds in the county) and report that a higher supply of RNs in the county was associated with higher RN skill mix in the hospitals. Using more recent data from the AHA, Grumbach et al. (2001) examined the associations among hospitals' reports of shortage status, vacancy rate, RN turnover rate, and staffing levels and the relationship of these variables to the RN supply in the county. They defined shortage as a “situation in which hospitals are unable to hire nurses at prevailing wages to achieve the staffing desired” (p. 388). When hospital-reported statistics were aggregated to the health service area, RN supply (nurses in county in relation to population) was correlated with hospital-reported shortage, r= −0.18, p<.05; RN vacancy rate, r= −0.21, p<.05; but not with RN turnover rate, r= −0.30, not significant; and RN staffing, r= −0.04, not significant. Seago et al. (2001) found that the primary predictors of hospital-reported shortage are location in the South, proportion of nonwhite county residents, proportion of Medicaid or Medicare patients, higher patient acuity, and team or functional nursing care delivery model. However, they did not include supply of RNs in these analyses.