Academic Salary Differentials — Some Evidence

Using data from a survey of the Irish academic labour market, this paper examines whether or not females in the Irish academic system are paid less than comparable males. Variables which adjust for comparability include academic discipline, qualifications, research output, teaching and adminis­ trative experience, and career-breaks. The results, which support the findings of similar studies based on US data, suggest that, other things being equal, Irish females are paid 10 per cent less than their male counterparts. Comparison of academics appointed before and after 1975 suggests that, correcting for age, the gap between male and female salary differentials may be narrowing. or some t ime, sex discrimination in all areas of employment , including A recruitment, p romot ion , salary levels and choice of occupation has been a controversial issue. Empirical analyses in this area are especially d i f f icul t because o f the heterogeneity of the labour market. Consequently, many studies concerned w i t h identifying and examining the implications o f sex discrimina­ t i o n have focused on relatively small homogeneous sub-groups of the labour force rather than the whole labour force. 1 One of the more frequently analysed groups is academics in different types of third-level colleges. This well-defined market has the advantage o f a high *We arc very grateful to Brendan Whelan for assistance with the computational analysis and to the Higher Education Authority for permission to use its survey data. The very helpful comments of the editor and two anonymous referees are also gratefully acknowledged. 1. For an introduction to and overview of the issues involved, see Blau and Ferber (1986). FRANCES R U A N E and E L M A DOBSON Trinity College, Dublin I I N T R O D U C T I O N degree of homogeneity, reasonably objective criteria for appointment and p romot ion , and a variety o f data sources. I n the Uni ted States, the academic labour market has afforded researchers an oppor tuni ty to evaluate the efficacy of bo th the Equal Oppor tun i ty and the Affirmative A c t i o n legislation passed during the 1960s and 1970s. The results of their studies have shown that although their posi t ion relative to males is improving, females are sti l l paid less than males w i t h comparable qualifications. Two main arguments about male-female salary'differentials can be distilled f rom the studies which have been carried out . The first is that salary differen­ tials pr imari ly reflect differences in both the amount and kind of investment in human capital undertaken by individuals. The second argument is that sex discrimination operating in favour o f males is the principle reason for salary differentials. I n practice, these arguments may not be entirely separable, as the existence o f sex discrimination may influence individual decisions about investment i n human capital, i.e., females rationally invest in lower levels of human capital because of the lower expected return to their investment com­ pared w i t h males. Contrasting w i t h the g rowth and sophistication of US studies in this area is the absence of analyses of differentials in part icipation rates and wage rates in academic labour markets in Europe. This reflects at least in part the lower pol i t ica l profile of employment equality issues in Europe, where participa­ t ion rates are t radi t ional ly higher than in the US. I t also reflects the lower range o f variation in university salaries in Europe, where academics are paid according to well-publicised salary scales, which typical ly relate more to length of service rather than to product iv i ty . This paper examines the issue of sex discrimination using data on academic salaries in the Republic of Ireland, hereafter referred to as Ireland. The results of this study are compared and contrasted w i t h the results obtained from similar US studies. Previous US studies in this area are reviewed in Section I I w i t h a view to developing the issue of sex discrimination and salary differentials more fu l ly . Section I I I provides a brief overview o f certain inst i tut ional aspects of the Ir ish academic labour market, while Section I V discusses the data set used in the analysis. Section V analyses the results obtained f rom the study and Section V I presents some conclusions. I I PREVIOUS STUDIES A n individual's salary can be explained by a number of different factors o f varying importance. By extension, variations in individuals' salaries can be explained by differences in the value and impact of these factors. 2 I n any 2. In terms of the regression equations estimated below, the value and impact of these factors is reflected in the size and significance of the coefficients in the equations determining salary. academic ins t i tu t ion , one of the most important factors which wou ld be expected to positively influence an individual academic's salary is the qual i ty and quant i ty of his/her actual and expected research o u t p u t . 3 I n practice, actual research output is usually measured by the to ta l number and/or the average annual number of academic publications, appropriately weighted, f rom some particular date (e.g., completion of Ph.D.). I n the case o f journa l articles, publications wou ld typical ly be weighted by the quali ty of the journals in which they are published, and by length, where this is appropriate. I n the case of monographs, the number of favourable book reviews and the status of the publishing company wou ld usually be the relevant weighting factors . 4 A t an early stage in an academic's career, expected research output is estimated f rom the level and quali ty o f qualifications attained and at a later stage f rom his/her previous publicat ion rate. Thus, the more time invested in augmenting the level of one's human capital, through education and research activities, the higher the salary one can expect. 5 The second major factor positively influencing salaries in academic inst i tu­ tions is the level of one's experience, as measured by the length o f time spent in bo th teaching and administrative roles. 6 This factor, together w i t h research, form the main precept of the human capital theory of salary determination, according to which salaries are determined by bo th the amount and pattern of human capital invested in the individual's career. I n the context of male and female academics, this human-capital theory suggests that female earnings wou ld be expected to be exceeded by male earnings, bo th because the careers of many female academics are interrupted by child-rearing and because this expected in terrupt ion may encourage lower investment in human capital (either education or research) by females. A th i rd factor which might affect an individual's relative salary is the opera­ t ion of some form of discrimination (by sex, race, age, etc.). I n this case, some arbitrary factors unrelated to the requirements for a particular posit ion or the qualities of personnel result in unequal treatment for equally-qualified persons. I n the case o f inequality between the sexes, discrimination wou ld reflect itself in the form of lower employment rates for women or lower 3. Clearly, the market conditions pertaining to different disciplines will influence salary levels within disciplines and salary differences across disciplines. 4. There is inevitably a great degree of subjectivity in determining such a weighting scheme. 5. Such investment would probably be subject to diminishing returns. 6. Some attempts have been made to measure the quality as well as the quantity of teaching under­ taken, by using an index system to rank academics' quality of instruction according to student and employer evaluations. It is, however, a very subjective method and Katz (1973) found it to be an unsatis­ factory means of constructing a variable to reflect teaching quality.