MnSCU –
2002 Salary Equity Analysis
March, 2003
Prepared
by:
Thomas McMullen
Senior Consultant
Hay Group
Consultant
Hay Group
Malcolm M. Dow
Professor Emeritus
Northwestern University
Table of Contents
I. Executive Summary............................................................................................................... 1
II. Faculty Salary Equity Analysis................................................................................................ 2
A. Brief Description of Average Faculty Salary Differentials by Gender and Ethnicity................... 2
1. Faculty Salary By Gender.................................................................................................. 2
2. Faculty Salary By Gender and Rank.................................................................................... 2
3. Faculty Salary By Gender and Ethnicity............................................................................... 3
B. Promotion to Academic Rank................................................................................................ 3
C. Controlling Salary For Structural Factors: Multiple Regression Analysis................................... 6
2.... Natural Log of Salary Regression Model......................................................................... 11
D. Total Population Model Without Discipline Variables............................................................ 13
E. Individual-level Salary Differences: Regression Residuals...................................................... 14
F. Summary............................................................................................................................. 16
This statistical analysis of the St Cloud State faculty salary data used the Multiple Regression model to predict salaries based on a number of factors known to affect pay. Variables coding for gender and minority status were included in the analyses. No faculty performance measures were included.
The analyses indicate that the difference between the White male reference category and the various protected categories ranges from -0.2% to 5.1%, although none of these differences are statistically significant.
There is no evidence of salary compression for faculty with many years in current rank or other time-based variables. However, the appointment status variables suggest that hiring faculty at the higher academic ranks but without tenure, and at higher average annual salaries than comparable tenured faculty, may lead to salary compression problems in the future.
A Multinomial Logistic Regression of the Academic Rank variable indicated that the odds of promotion to higher Rank for White males versus the six protected classes were not statistically significantly different. In addition, the Total Population Model without the Academic Rank variable suggested some salary bias masked by rank only for the Hispanic female category, although the difference from the reference White male category was still not statistically significant.
The first three tables reported in this section are intended to provide a very brief indication of the variation in average 2002 yearly salaries across ethnic and gender groupings of St Cloud State faculty. Explaining as much of this variation in salary as possible, using additional background factors such as academic rank and length of service, is the focus of this report.
Table 1 shows a $5,915 shortfall in average annual salary for female relative to male faculty. Several factors that account for much of this difference will be discussed below.
Table 1. Average 2002 Salary by Gender
|
M/F |
Mean |
N |
Std. Dev |
|
F |
51211 |
271 |
10822 |
|
M |
57126 |
382 |
12696 |
|
Total |
54671 |
653 |
12296 |
One major factor that affects faculty salary differences is Academic Rank. Table 2 reports average annual salaries broken out by Gender and Rank. At the Instructor, Assistant Professor, Associate Professor and Professor ranks, male salaries are on average higher than the female averages.
Table 2. Average 2002 Salary by Rank and Gender.
|
rank |
M/F |
Mean |
N |
Std. Dev |
|
professor |
F |
61867 |
83 |
7294 |
|
M |
66820 |
167 |
8543 |
|
|
|
|
|
|
|
|
associate professor |
F |
53851 |
64 |
5911 |
|
M |
56877 |
75 |
8726 |
|
|
|
|
|
|
|
|
assistant professor |
F |
46399 |
82 |
5153 |
|
M |
47831 |
110 |
7782 |
|
|
|
|
|
|
|
|
instructor |
F |
35526 |
42 |
4430 |
|
M |
37863 |
30 |
5010 |
|
|
|
|
|
|
Table 3 reports average salary differences broken out by a combination of Gender and Ethnicity. Again, this table shows substantial salary differences in average salaries across these groupings. The average salary for White males is higher than that of any other protected class, with the exception of Asian males.
Table 3.
Average 2002 Salary by Ethnicity-Gender
|
ethnicity-gender |
Mean |
N |
Std. Dev |
|
white female |
51718 |
233 |
11142 |
|
african amer
female |
* |
1 |
|
|
asian
female |
49933 |
17 |
8132 |
|
hispanic female |
45772 |
8 |
10439 |
|
native amer female |
* |
3 |
|
|
white male |
57570 |
297 |
12755 |
|
african amer male |
53614 |
19 |
10330 |
|
asian male |
61767 |
39 |
13026 |
|
hispanic male |
47285 |
8 |
6051 |
|
native amer male |
* |
3 |
|
|
unknown |
47484 |
22 |
7823 |
|
Total |
54671 |
653 |
12296 |
* Data are
omitted if less than five faculty members within a grouping.
We note that this analysis uses current data patterns within campus to assess odds ratios for promotion. This analysis did NOT examine actual rates of promotion acceptance and rejection within a campus, as this data were not available for analysis. That is, we analyzed only the current distribution of faculty within ranks, broken out by ethnicity-gender. For example, at St Cloud there are 77 White male Assistant Professors and 53 White male Associate Professors, with corresponding odds of 53/77 (=0.688) of moving from Assistant to Associate rank. For White females there are 60 Assistants and 60 Associates, with corresponding odds of 60/60 (1.0) of being Associates. The “odds ratio” of White females to White males getting promoted from Assistant to Associate is then (1.0)/(0.688) = 1.453; that is, White female odds are 145.3% of the White male odds. The multinomial Logistic regression model adjusts these odds ratios to take into account the effects of other variables that might factor into promotion decisions, such as highest degree, previous experience, length of service, etc. When these control variables were entered into the Multinomial logistic regression model the odds ratio improved slightly, from 1.453 to 1.865 (see Table 4 below).
Table 4 shows the estimated odds ratios of promotion from Assistant Professor to Associate Professor and from Associate Professor to Professor obtained using the Multinomial Logistic Regression model. The odds ratios were calculated after controlling for Highest Degree, Years of Prior Experience, and Length of Service. There are no promotions shown for Instructor to Assistant, since there is “complete separation” in the data, meaning that the Doctorate variable completely predicts this promotional step.
Odds ratios greater than 1.0 indicate a correspondingly greater likelihood for individuals in the indicated category in obtaining promotion to the next category. Conversely, odds less than 1.0 indicate less likelihood.
Six minority dummy variables – African American males, White
females, Asian males, Asian females, Under-represented females and males – were
included in predicting odds of promotion to higher rank. Because categorical
modeling cannot handle groupings with very low frequency for combinations of
attributes (e.g. black + female + associate professor), some minority groupings
are combined into the Under-represented categories.
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Table 4.
Odds of Promotion to Higher Rank by Gender and Ethnicity |
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