Gender Differences and Predictors of Work Hours in a Sample of Ontario Dentists

The shift toward more women in the dental profession is ongoing, and the impact of this remains unclear. Limited evidence suggests that female dentists work fewer hours than male dentists, are less interested in the business aspect of the profession and are not sufficiently represented in academia and specialty practice.^1-7 A decade-old Canadian survey comparing male and female dentists found differences in terms of practice characteristics, work hours, attitudes and income.⁴ However, studies controlling for practitioner age, marital status, children and practice patterns are lacking. Likewise, clarity regarding barriers, opportunities and the impact of societal gender roles is also needed. Additional insight can be derived from the medical literature, which has highlighted differences between male and female physicians in terms of practice patterns, remuneration, career satisfaction, specialty selection and family–career balance.^8-10

One issue in particular that has been theorized to be affected by this demographic shift is labour supply. Male dentists have reported working 6.9 more hours a week than female dentists, with women citing child care issues as the main reason for part-time work.³ In another survey, 47% of female dentists reported part-time employment, with the primary reason again being child care issues followed closely by personal choice.¹¹ Having children was, again, found to reduce women’s work time by 7 h/week, while having no impact on men’s hours.¹² In another survey, married female dentists 25–32 years of age reported working 3.5 fewer hours a week than similarly aged married men, whereas unmarried female dentists reported working the same number or more hours than unmarried men.⁴ Likewise, in a study of physicians 7 years after graduation, only 64% of women with children reported working full time (vs. 95% of men).¹⁰

Given the rapid increase in the number of female dentists in Canada over the past decade and its potential impact on labour supply, the aim of this paper was to determine whether gender is a determinant of the number of hours worked per week by a sample of Ontario dentists and which personal, professional and sociodemographic factors predict the number of hours worked by male and female dentists.

Methods

Study Design

A random sample of 3000 dentists practising in Ontario was selected from the Royal College of Dental Surgeons of Ontario provider listing of 8398 dentists (December 2010).¹³ This survey population was selected, as most Canadian dentists practise in Ontario, the provincial population is ethnically diverse reflecting the overall diversity in Canada¹⁴ and gender differences were not expected to vary by province. An initial sample size of 941 was estimated based on the most conservative measure of variation in response to questions (50/50 split), a 95% confidence level and a 3% sampling error.¹⁵ This sample size was tripled to 3000, given an expected response rate of 40% or less. The sampling frame was first stratified by gender based on the dentist’s name, and a random start systematic sample was drawn from each stratum (1500 men and 1500 women). Ethics approval was received from the University of Toronto’s Office of Research Ethics (protocol reference #27977) and a single mail-out was completed in the summer of 2012.

Survey Instrument

A 52-item survey was designed to assess gender differences with respect to professional issues (e.g., work-practice characteristics, clinical decisions, retirement, business knowledge, relationship with staff, specialty and advanced education, career satisfaction, career breaks, leadership and academia) and personal issues (e.g., marital status, children, familial responsibilities and stress/conflict resulting from balancing multiple roles) faced by dental practitioners. The survey was pilot-tested for clarity and ease of completion.

Statistics

All analyses were conducted using STATA v. 13.0 (StataCorp LP, College Station, Texas, USA).

Descriptive Analysis

A descriptive analysis was followed by a gender-stratified analysis assessing differences using Student’s t tests for continuous and binary variables and χ² tests for categorical variables.

Regression Model Specifications

Preliminary univariate regressions were conducted to assess the significance of variables in predicting the outcome. These included demographic controls, such as gender, age, marital status, location of dental training and graduation year. Work-related predictor variables, such as practice location, most enjoyable aspects of career and speciality training, were also used. In addition, a composite of 5 variables assessing respondents’ self-reported business acumen was constructed. Predictor variables assessing familial characteristics, such as the extent of concessions made in a respondents’ career to pursue family life, the extent of concessions made by a respondent’s partner to aid in the dentist’s career, responsibility for household chores and primary caregiver duties, were also used. The absence or presence of children, stratified by dependent age, was also used as a control variable.

Regression Estimation Procedures

Development and testing of the initial model were done using ordinary least squares (OLS) regression. Given the non-normal distribution of residuals (Smirnov-Kolmogorov test), potential outliers and heteroskedasticity, the initial OLS model was re-run using robust regression. The latter technique gives less weight to observations with large residuals that would otherwise bias the results. Both the OLS and robust regression indicated that no observations were eliminated and similar effects of the various predictor variables were found.

Results

Descriptive Findings

The 867 dentists who responded included 401 women (46%), 463 men (54%) and 3 people whose gender was unreported; after taking into account undeliverable surveys, this yielded a response rate of 29%. Most respondents were general practitioners (85.9%), 40–59 years of age (60%), had completed their dental undergraduate training between 1981 and 2000 (57%) and were Canadian-trained (80%) (Table 1).

Work-related statistics revealed that dentists worked an average of 36 h/week. Most (82%) worked full time (≥ 30 h/week) and were practice owners or partners (78%). Familial statistics revealed that most dentists were married (84%) and had children (83%). Most reported some degree of spousal support in terms of both primary caregiving and household responsibilities (61% and 65%, respectively).

Gender-stratified analyses revealed that a higher proportion of male dentists were specialists (17% men vs. 11% women, p = 0.02), tended to be older (62% men vs. 33% women ≥ 50 years, p < 0.001) and were more often Canadian-trained (86.2% men vs. 72.8% women, p < 0.001).

On average, male dentists worked an additional 2 h/week (p < 0.01), with the majority of both men and women working full time (87% men vs. 77% women, p < 0.01). Men were more likely to be practice owners (84% men vs. 71% women, p < 0.01), and they reported a marginally higher level of self-confidence in their business knowledge and skills (men scored 3.8 on a scale of 1 to 5; women 3.7, p < 0.01). A similar proportion of male and female dentists indicated that they enjoyed the financial reward of dentistry, managing others and maintaining a structured work schedule. However, more women indicated that the career aspects they enjoy the most were the ability to secure part-time work (48% women vs. 24% men, p < 0.01) and parental leave (19% women vs. 5% men, p < 0.01).

Familial data revealed that a higher proportion of men had children (88% men vs. 78% women, p < 0.01) and had 1 or more child aged ≥ 8 years (69% men vs. 49% women, p < 0.01). In contrast, a higher proportion of female dentists had children aged ≤ 7 years (29% women vs. 19% men). More female dentists considered themselves to be primary caregivers (24% women vs. 8% men) and solely responsible for household chores (41% women vs. 10% men). Female dentists also perceived themselves to have made concessions in their career in favour of family significantly more than men (p < 0.01), while male dentists perceived that their partner had made significant career concessions to aid in their career (p < 0.01).

Predictors of Work Hours/Week

Detailed results of univariate and multivariate regression analyses are presented in Tables 2 and 3, respectively. As the results of both the OLS and robust regression models were similar, relationships were characterized based on the final robust regression specification.

Male dentists worked significantly more hours a week than female dentists (p < 0.01). Dentists aged < 60 years worked significantly more hours a week than older dentists (p < 0.01), with the discrepancy decreasing with advancing age. Practice ownership increased the number of work hours (p < 0.01). Canadian-trained dentists worked fewer hours a week than their internationally trained counterparts (p < 0.01).

Considering familial determinants, dentists who perceived having some level of spousal support for household chores or primary caregiver duties worked significantly more hours a week than those who perceived themselves as solely responsible. Dentists with children aged 0–3 years of age worked significantly fewer hours a week than those without children (p < 0.01); however, this effect became non-significant after controlling for spousal responsibility for primary caregiver duties. Finally, married dentists were found to work significantly fewer hours a week than those who were single in both the univariate and initial multivariate analyses; this effect became marginally significant (p = 0.059) after controlling for spousal responsibility for caregiver status.

Canadian-trained female dentists worked significantly fewer hours a week than those trained internationally (p < 0.01), while the effect of tra…