Background: Previous studies have documented income differences between male and female physicians. However, the implications of these differences are unclear, since previous studies have lacked detailed data on the quantity and composition of work hours. We sought to identify the sources of these income differences using data from a novel survey of physician work and income.
Objective: To compare differences in income between male and female physicians.
Design: We estimated unadjusted income differences between male and female physicians. We then adjusted these differences for total hours worked, composition of work hours, percent of patient care time spent providing procedures, specialty, compensation type, age, years in practice, race, ethnicity, and state and practice random effects.
Participants: We surveyed 656 physicians in 30 practices in six states and received 439 responses (67% response rate): 263 from males and 176 from females.
Main measure: Self-reported annual income.
Key results: Male physicians had significantly higher annual incomes than female physicians (mean $297,641 vs. $206,751; difference $90,890, 95% CI $27,769 to $154,011) and worked significantly more total hours (mean 2470 vs. 2074; difference 396, 95% CI 250 to 542) and more patient care hours (mean 2203 vs. 1845; difference 358, 95% CI 212 to 505) per year. Male physicians were less likely than female physicians to specialize in primary care (49.1 vs. 70.5%), but more likely to perform procedures with (33.1 vs. 15.5%) or without general anesthesia (84.3 vs. 73.1%). After adjustment, male physicians' incomes were $27,404 (95% CI $3120 to $51,688) greater than female physicians' incomes.
Conclusions: Adjustment for multiple possible confounders, including the number and composition of work hours, can explain approximately 70% of unadjusted income differences between male and female physicians; 30% remains unexplained. Additional study and dedicated efforts might be necessary to identify and address the causes of these unexplained differences.
Keywords: disparities; health services research; reimbursement; survey research; workforce.