Venue: The Fuqua School of Business, Duke University, 1 Towerview Drive, Durham, NC 27708-0120
Presentation
Gender discrimination and the salaries of operating room managers
BACKGROUND: Nursing is a predominantly female occupation in which the small numbers of men have traditionally received a wage premium. Men represent only 9.7% of registered nurses, but median annual earnings for male nurses are $55,848 compared to $50,492 for females (BLS 2006). Recent studies show the wage premium for male nurses is unexplained by differences in socio-demographic, human capital, or employment characteristics (Kalist 2002; Jones and Gates 2004). However, the studies rely on national survey data which provides only broad occupational categories and weak measures of job-related productivity, so it is impossible to determine if male and female nurses receive differential pay for the same work, or if men have different job responsibilities. We are able to untangle these effects within a narrowly-defined, relatively highly-paid occupation, using a unique data set on employment and compensation of operating room (OR) nurse-managers. DATA: We use data from a survey of 263 OR managers (225 females/ 38 males) to estimate male/female salary differentials, and to decompose the salary gap into a part explained by differences in job characteristics and an unexplained part, possibly attributed to discrimination. The data are unique in providing details of the job responsibilities of each OR manager including: case volume; operating budget; number of ORs supervised; number of workers supervised. The survey, which also includes information on hospital characteristics and nurses' human capital, provides an unusually rich source of data for estimating economic models of discrimination.
METHODS: We estimate ordinary least squares regression models of the determinants of annual salary separately for male and female managers. We then decompose the salary differential into an explained part (associated with differences in job responsibilities, etc.) and an unexplained part (attributed to omitted variables and/or discrimination) (Oaxaca 1973; Reimers 1983). The small sample sizes pose econometric difficulties, because we cannot afford to lose many observations to missing data. One problematic variable is OR budget, missing for approximately 16% of our final sample. We use a multiple imputation procedure to generate values for the missing data, and correct the final regression estimates for the imputation.
PRELIMINARY FINDINGS: The mean salary for female OR managers is 93% of the mean salary for males. Males and females have similar education and experience, on average, but males tend to manage more operating rooms, with a higher case volume. Males supervise 50% more personnel than do females, on average, have double the annual budget, and are more likely to work in teaching hospitals. Altogether, the male/female differences in job characteristics explain approximately 50% of the salary gap, so a small unexplained differential (3% of average male salary) remains.
IMPLICATIONS: We find evidence to suggest gender discrimination in salaries paid to male/female OR managers, although the unexplained differential is relatively small. We also find evidence of job segregation within this narrowly-defined occupation, which cannot be explained by differences in average qualifications of males and females. The results suggest inefficiencies in the allocation of labor within nursing markets, which may discourage talented women from entering the profession.