Back to top

Regression analysis – Pay Inequity

This is the most common form of analysis in pay gap studies undertaken at Canadian universities. Here, the researcher typically uses Ordinary Least Squares (OLS) regression to create a statistical model that reflects the system of pay determination at the university. Using individual-level salary data, the researcher regresses salary14 onto variables that represent factors that determine pay, such as rank, department/discipline, age/years at rank/years of experience. Depending on data availability, the regression may also include other variables that may influence pay such as Canada Research Chair status, number of publications, etc. or other demographic data, such as racialized group membership.

Importantly, a variable denoting gender is also included in the regression. The resulting coefficient for this variable represents the average pay gap between men and women at the institution and is a measure of pay inequity. Some academic staff associations have received monetary remedies based on the magnitude of this coefficient; the cases of McMaster University,15 Wilfred Laurier University,16 University of British Columbia,17 and Simon Fraser University18 are some examples.  

When specifying a regression, researchers should consider any variables that are important for the determination of pay at their university. Since different universities have different pay structures, there may also be differences in how models are specified. However, there tend to be core variables included in almost all salary models, namely gender, rank, discipline, and some measure of years of experience or age.  

There are other regression and statistical techniques that may be useful for regression analysis of salaries.19 One such method is hierarchical linear modeling which is a form of OLS regression that accounts for the “clustering” or “nesting” of observations, which may be applicable in some instances given that faculty are organized by department/faculty. The analysis undertaken at the Wilfred Laurier University use this technique.20

Regression of this type can be done on different types or components of salary, such as starting salaries, market differentials, retention payments, or stipends. The committee for the 2015 Simon Fraser University examined the components of an academic salary, which includes base salaries and “off-scale” amounts like market differentials and retention awards. From its analysis, the committee determined that gender pay disparities were driven by disparities in market differentials, not base salaries.21


14 In some cases, the natural log of salary is also used.

15 Flaherty, Colleen. Leveling the Field. Inside Higher Ed. April 30, 2015: https://www.insidehighered.com/news/2015/04/30/mcmaster-u-addresses-gender-pay-gap-3500-raises-female-faculty-members

16 Wilfrid Laurier University. Laurier gender-equity analysis results in salary increases for the university’s female associate and full professors. May 8, 2017: Gender-equity analysis results in salary increases for female associate and full professors (wlu.ca)

17 Bradshaw, J.. UBC gives all female tenure-stream faculty a 2 per cent raise. The Globe and Mail. February 2, 2013: https://www.theglobeandmail.com/news/national/education/ubc-gives-all-female-tenure-stream-faculty-a-2-per-cent-raise/article8150659/

18 Simon Fraser University Faculty Association. Salary Equity Agreement. December 19, 2016. http://www.sfufa.ca/salary-equity-agreement/

19 Some additional methods are discussed in the following publications:

Strathman, J. G.. Consistent estimation of faculty rank effects in academic salary models. Portland State University. 2000: Consistent Estimation of Faculty Rank Effects in Academic Salary Models (pdx.edu)

Johnson, C. B., Riggs, M. L., & Downey, R. G.. Fun with numbers: Alternative models for predicting salary levels. Research in Higher Education, 27(4), 349-362. 1987: Fun with numbers: Alternative models for predicting salary levels | SpringerLink

20 Rutherford, J., Brunskill C., et al.. Final Analysis and recommendation of the Bi-Lateral Committee on Gender-based Pay. 2017.

21 Kessler A. and Pendakur K., Gender Disparity in Faculty Salaries at Simon Fraser University. Department of Economics, Simon Fraser University. 2015: salary_equity_stu, dy.pdf (sfufa.ca)