Solomon Polachek was minding his own business back in 1975 looking for evidence to show occupational crowding and that women were pushed into low paid occupations by sex discrimination, and in particular, employer discrimination. About 60 per cent of women still work in just 10 occupations. the occupations which are female-dominated are often relatively poorly paid jobs
By chance, Polachek departed from the usual empirical strategy for estimating the male-female wage gap at that time.
Rather than include a dummy variable to estimate discrimination after various factors have been taken into account, he introduced dummy variables that took account of both gender and marital status. His results were startling.
He previously was able to explain about 35% of the wage gap using the data at hand and variables he was using.
This 35% gap dropped to 18% for single never married males and females, but his ability to explain the gender wage gap increased dramatically to over 60% for married spouse present males and females.
What more, the presence of children exacerbated the gender wage gap. Each child of less than 12 years old widened the female male pay disparity by 10%. Furthermore, large spacing intervals between children widened this gender wage disparity even further.
Subsequent research showed that marital status had the same effects on gender wage gaps in Germany, the UK, Austria, Switzerland, Sweden, Norway and Australia. Factors associated with dropping out of the labour market to care for children could explain up to 93% of the gender wage gap.
These findings are devastating to the notion that there is some sort of discrimination against women on the demand side of the labour market. As Polachek explains:
The gender wage gap for never marrieds is a mere 2.8%, compared with over 20% for marrieds. The gender wage gap for young workers is less than 5%, but about 25% for 55–64-year-old men and women.
If gender discrimination were the issue, one would need to explain why businesses pay single men and single women comparable salaries. The same applies to young men and young women.
One would need to explain why businesses discriminate against older women, but not against younger women. If corporations discriminate by gender, why are these employers paying any groups of men and women roughly equal pay?
Why is there no discrimination against young single women, but large amounts of discrimination against older married women?
… Each type of possible discrimination is inconsistent with negligible wage differences among single and younger employees compared with the large gap among married men and women (especially those with children, and even more so for those who space children widely apart).
The main drivers of the gender wage gap is simply unknown to employers such as whether the would-be recruit or employer is married, their partner is present, how many children they have, how many of these children are under 12, and how many years are there between the births of their children. These are the main drivers of the gender wage gap – all of which are factors totally unknown to employers and of no relevance to them in making a profit.
The drivers of the gender wage gap on the supply side of the labour market regarding the choices women make about having children, when they have children, and how this influences their investment in human capital, and in particular, in human capital that does not depreciate by that much because of intermittent labour force participation due to motherhood.
Occupational crowding hypotheses of the gender wage gap have the drawback of being an invisible hand explanation of social outcomes. Each individual, acting only to best secure her own rights and interests, act in such a way that the unintended outcome of a complex social interaction.
The specific unintended outcome that must arise from millions of choices of people acting in their own interest throughout their lives is occupational segregation.
The market process of the invisible hand has both a filter and and equilibrating mechanism. The filter is profits and loss to exclude through insolvency and bankruptcy those entrepreneurial choices that do not further consumer’s interests. The equilibrating mechanism – the mechanism that tells people which choices they should make – is price signals. Price signals guide individual choices towards the unintended outcome.
Those that argue that women are socialised to make particular choices such as mother were not paying attention to the 20th century and the radical social change over the course of that century, in particular in the role of women. As Gary Becker explains:
… major economic and technological changes frequently trump culture in the sense that they induce enormous changes not only in behaviour but also in beliefs.
A clear illustration of this is the huge effects of technological change and economic development on behaviour and beliefs regarding many aspects of the family.
Attitudes and behaviour regarding family size, marriage and divorce, care of elderly parents, premarital sex, men and women living together and having children without being married, and gays and lesbians have all undergone profound changes during the past 50 years.
Invariably, when countries with very different cultures experienced significant economic growth, women’s education increased greatly, and the number of children in a typical family plummeted from three or more to often much less than two.