Background
The primary care physician (PCP) workforce in many industrialized nations is increasingly female. In several industrialized countries, the proportion of PCPs who are women has doubled or nearly doubled over the last 30 years [
1,
2]. Globally, 32% of all physician graduates worldwide are female, and that percentage is higher, on average, in family medicine [
3]. Thirty-four percent of family medicine/general practice physicians and 55% of family medicine residents in the United States (US) are women [
4]. In Canada, women now make up 58% of medical school enrollees (up from 14% in 1968) [
5] and more women than men are choosing to specialize in primary care [
6].
Amidst often highly-charged claims of physician shortages from the public and medical leadership alike, future physician workforce planning has been identified as a priority for both research and policy action in many industrialized countries, and is essential for the rational management of health care systems [
7]. If they are to be an effective policy tool, physician workforce planning will need to go beyond simply projecting the traditional factors of population growth and ageing, and physician headcounts [
8‐
10], to include variables that affect both service requirements (population need) and availability [
11‐
13].
The rapid feminization of the PCP workforce over the past half-century is a significant demographic change that has the potential to influence service availability. For example, claims that changes in the gender balance of the PCP workforce will change the effective overall supply of primary health services (for example, because female physicians work fewer hours than their male counterparts) and/or the mix of available services (for example, because of differences in styles of practice) have a certain intuitive validity. Unfortunately, debate in this arena has, for the most part, not advanced much beyond these simplistic claims.
Thus far, even where workforce planning models account for changes in physician workforce demographics (such as feminization), they commonly apply a simplistic calculus, using simple service or headcounts, or assuming the work of a female physician as a fixed proportion of a male physician (typically using full-time equivalent measures) [
14,
15]. It is very difficult to find supply projection models that embody evidence about the differences between male and female physicians in life-course productivity, changes over time in trends in retirement, or recent changes reflecting shifting work-life priorities amongst younger cohorts of physicians. The focus of this paper is to synthesize the evidence relating to the first of these factors - male-female differences in physician service provision over a life-cycle. Our specific population of interest is general practice and family medicine (which we will henceforth refer to as PCPs); other primary care specialties such as internal medicine and pediatrics will be discussed in a subsequent manuscript.
This systematic review examines evidence related to the effect of the PCP workforce, defined here as feminization on the supply of physician services. Specifically, we reviewed studies that compared male and female PCPs in terms of the amount of time they spent working, how intensely they worked (that is the number of services or patient encounters per unit time), and whether their practice and service characteristics differed.
Discussion
The intent of this systematic review was to examine the impact of the increasing proportion of women in the PCP workforce on service delivery in five areas that could affect such projections of service supply: years of practice, hours of work, intensity of work, scope of work, and practice characteristics. Compared with their male colleagues, female PCPs:
-
Self-report fewer hours of work (excluding on-call time)
-
Have fewer patient encounters, and deliver fewer services (perhaps as an artifact of working fewer hours), but spend longer with their patients during a contact and deal with more separate presenting problems during each visit
-
Write fewer prescriptions, but order more laboratory tests, and refer patients on to specialists more frequently
-
See more female patients and fewer geriatric patients
-
Provide less out-of-office (including home, nursing home and hospital visits) and off-hours care
The scale of the impact of these findings on future effective physician supply is difficult to determine with currently available evidence, given that very few studies looked at time trends or years of practice, and results from those that did are inconsistent. Also, the full impact will depend critically on future trends in the feminization of the workforce. In Canada, and in the UK and other parts of Europe, the proportion of medical students who are female ensures that the overall supply of physicians will continue to become increasingly female in the near term.
Given that fact, the differences in practice patterns between male and female PCPs could result in increased derived demand for specialist physician services, laboratory technicians, imaging technicians or other health professionals, outside of primary health care. The fact that female PCPs spend less time in off-hours care, and are less likely to serve patients at home and in nursing homes, could increase the reliance on already-stretched emergency departments and walk-in clinics as a source of primary health care, and force a rethinking of how medical care is delivered to patients outside standard office hours and locations.
It is important to consider the effects of childbearing and childrearing, which were mentioned in several studies, but were seldom explicitly investigated, and were not the primary focus of any of the research documents reviewed here. Female PCPs who had children under age 18 worked fewer hours per week and were more likely to have self-reported part-time status compared with women who did not. The dampening effect of children on work hours was twice as large for women as it was for men. And, one study found that once family circumstances were accounted for, the gender of the physician had no significant effect on hours worked [
17].
An important issue that was not covered in any of the literature reviewed here is the balance between work and household responsibilities among physicians. One study found that female physicians spent more time on unwaged childcare and household jobs than male physicians [
41]. Once unwaged household responsibilities were accounted for, female PCPs who have children worked an average of 90.5 hours a week, compared with 68.6 hours per week for males with children [
41].
Consistency of results
Results were strongly consistent across some of the thematic areas, and relatively less so in others. In particular, results relating to the hours and intensity of work were consistent across studies. In other areas, such as practice characteristics, results were highly variable.
The results of this review demonstrate that the drivers of observed differences between male and female PCPs are complex and nuanced. The size of an observed gender difference varied based on the characteristics of the health care system under study and on whether the possible confounding effects of physician age, practice characteristics, and in particular, family characteristics and part-time status were adequately controlled. There were at least 36 different health care systems represented by the studies included in this review. Inconsistent results across studies may be caused by health care system differences including, but not limited to, physician remuneration mechanisms and policies, the gatekeeping role of general practitioners, and general employment policies. An exploration of the role of such system differences was well beyond the scope of this review, but is an important area for future research.
Inconsistent results could also be a function of methodological and measurement differences across studies, and whether the confounding effects of other physician, patient, and practice characteristics have been accounted for. For example, gender differences in the number of patient contacts per day disappeared once full- versus part-time status had been accounted for in work by Boerma and van den Brink-Muinen [
18]. Differences in hours worked depended on whether auxiliary activities such as on-call time were included as part of ‘hour worked’ [
23]. Similarly, differences in care provision were attenuated once patient characteristics and practice location was accounted for (for example, [
1,
31]).
Methodological issues
As part of our qualitative assessment of study quality, we identified some significant methodological concerns with the studies included in this review. For the most part, they relied on cross-sectional retrospective surveys. Such surveys are always subject to recall bias, though unless there were systematic male versus female differences in accuracy of recall, this may not be an issue in this particular circumstance. But surveys do tend to produce inflated estimates of hours worked for those who report high hours (more often male physicians) and deflated estimates for those reporting low hours (more often female physicians), which may exaggerate any true gender difference [
42]. Many studies relied on small, often unbalanced samples, raising concerns about selection bias. All but one study failed to adjust statistically for multiple comparisons, despite conducting as many as 155 separate statistical significance tests [
32].
Perhaps even more concerning, however, is that 12 (35%) studies presented only unadjusted, bivariate results, failing to control for the potential confounding effects of other physician, patient or practice characteristics (for example, [
23,
26,
34]). Additionally 6 (18%) undertook only rudimentary stratification (for patient age and gender, for example) (for example, [
24,
25,
34,
43]). Statistical methods controlling for confounders may not yet have been accepted practice in this field when some of these earlier papers were published, which may explain their limited use. Comparisons between adjusted and unadjusted results suggest that physician age, family characteristics and practice location, at a minimum, can have important influences on apparent male-female differences in key practice and productivity indicators. For example, older physicians - who are more likely to be male - tend to see more older patients [
18], and physicians who work in rural-based clinics practice differently from physicians who practice in urban centres [
32]. Thus the impacts of physician age and practice location may be conflated with a gender effect in unadjusted analyses, since female PCPs tend to be younger [
31] and more likely to work in urban centres in some countries [
18].
Gaps in knowledge and future research
Given the reliance on cross-sectional and survey data, and the relative underutilization of longitudinal or administrative datasets in this area, there remains a need to critically examine activity levels, over time and at a population level, adjusting for the potentially confounding effects of age and cohort. The issue of retirement patterns has also not been adequately examined with reference to the effects on time spent working. It is possible, for example, that although female PCPs work less, especially around childbearing years, they may retire later than their male counterparts, reducing or even eliminating a career difference in time spent working. While historically this may not have been true, trends over time suggest that it might become so in future. The key point is that differences in retirement patterns between male and female physicians may partially or wholly offset other trends in service provision, when viewed over an entire life-cycle. Leaves of absence taken for parental or other reasons should also be examined for their effects on both time and intensity of working. No studies included in this review examined absences from practice.
To date, the literature examining other practice differences between male and female physicians that could have an important impact on health human resources planning has been limited. More studies comparing the patient populations of male and female PCPs - beyond simple gender concordance and patient age - are certainly warranted. Specifically, very little work has been done examining differences in patient morbidity levels, or chronic disease burdens. Additionally, more nuanced investigations of service mix, problems seen, and care delivered would address currently unanswered, but important, questions bearing on the future provision of physician services. For example, differences in practice style between male and female physicians have currently received little attention beyond comparisons of time taken for each appointment.
Issues of work-life balance and childrearing and household responsibilities are also under-researched, especially given their observed impact on full- versus part-time job status and working hours [
17,
41]. In the 2007 and 2010 Canadian National Physician Surveys, the majority of respondents identified attaining balance between personal and professional life as the most important factor for a satisfying practice [
44]. Physicians, regardless of gender, are increasingly (and not unreasonably) seeking a work environment that provides this balance, without compromising the quality of care they provide to their patients [
45]. Secular trends in time made available for clinical practice obviously have direct implications for projections of physician service provision.
Limitations
This systematic review used comprehensive search strategies encompassing multiple peer-reviewed and grey literature sources to maximize capture of relevant articles and minimize publication bias. The restriction of articles to those published in English and within the last 23 years may have eliminated some potentially relevant studies. Additionally, because the area of research is not yet well-indexed and the specific topic area is broad, some studies that would be relevant, but whose main comparison was not male versus female PCPs, may have been missed.
Our decision to include only those studies that focused on PCPs, defined here as general practitioners or family medicine specialists, (rather than also including other specialists like general internists or pediatricians - who may practice like PCPs under certain circumstances) may limit the generalizability of our results, particularly with respect to research from the US.
An additional limitation is the decision not to eliminate studies that were deemed of poor quality. The methodologies employed in many of the studies is certainly far from ideal, with many relying on small, unbalanced samples, retrospective surveys, and incomplete (or no) control for the impact of confounding factors. These studies were, however, retained in the review since none of the 30 included would have achieved the level of guidance required for formal guidelines (for example, those issued by the Cochrane Collaboration) and, thus, there was no straightforward way to gauge methodological quality.
Meta-analytic techniques could have been a useful way to summarize the research within individual thematic and subthematic areas; however, small numbers and the variance in outcome measures even within individual subthemes were too great to allow for the use of those tools.
Implications for health human resource planners
Projections of physician supply must take into account variables other than estimated future physician headcounts. At a minimum, more robust measures that account for gender differences in service volumes, but that also address the implications of the differences in patient mix, service mix, and practice style between male and female physicians need to be developed and used as evidence in these areas becomes available. Other demographic and workforce factors, such as the impact of physician age and cohort - should also be considered.
Conclusions
Compared with their male counterparts, female PCPs spend less time working, and deliver less care. Evidence as to whether this gap is narrowing is mixed. The effect of childrearing is critically important, affecting female PCPs far more than their male counterparts, in terms of impact on participation in clinical practice. Once the effect of family characteristics has been accounted for, sex has no effect on time spent working. Issues of work-life balance, caregiving and childrearing responsibilities warrant attention in future research.
The literature focuses heavily on differences in the amount of work done by female compared with male physicians, and is almost exclusively based on retrospective surveys with some significant methodological limitations. These studies tell us nothing about differences in the appropriateness or quality of care. Also, more research examining differences in practice characteristics, and patient/service mix, is warranted in order to support the development of robust forecasts of physician supply. Such forecasts would ideally take into account sex-related differences in volume, bct also the implications of the differences in patient/service mix and practice style, and temporal trends in each of these. The extant literature suggests that secular trends in hours of work may dominate sex-related differences in service provision.
Competing interests
The authors declare that they have no competing interests.
Authors’ contributions
All authors contributed to the collection and interpretation of the data. LH developed the search and abstraction tools. LH and KC selected studies for review and conducted the abstraction and interpretation of the data. MB, IB, KM, and ML contributed significantly to the analysis and interpretation. LH wrote the first draft and managed subsequent drafts with revisions from all other authors. All authors give final approval of the publication of this version of the paper.