The gender gap in pay progression: job mobility and job ladders

The median gender pay gap has declined dramatically in the UK from 36.4% in the 1970 (O'Reilly, Smith et al. 2015) to around 18% in the most recent data (ONS 2018). Still, by international standards the pay gap is high: the UK has the fourth largest gender pay gap in the EU and the eighth largest of OECD countries (OECD 2019).

Researchers and policy makers have focused on gender differences in education and labour market experience as the likely drivers of the pay gap. However, today these explanations no longer stand up to scrutiny. Women are on average better educated than men and they are much less likely to withdraw from the labour market for long periods of time. Nevertheless, women earn on average about 10% less than men even when they work full-time and have similar education and labour market experience.

While explanations focusing on women's potential lower productivity as the cause of the gender pay gap have been thoroughly investigated and found inadequate, there is less evidence on the role played by employers. This research will contribute to addressing this gap.

The standard economic model of the labour market assumes that wages are determined by the market and that individual employers cannot choose the wages they offer to their employees. A different model assumes that for a variety of reasons competition is not perfect and employers have some discretion over the wages they offer. This wage setting power is likely to be weaker when workers are mobile.

Mobile workers will leave an employer offering wages below the market rate. However, if workers are relatively immobile, employers can exploit this 'immobility' by offering them lower wages. If women are more constrained by family responsibilities in the types of jobs that they will take-up or in the amount of time and effort they can devote to job search, they will generally be more immobile and thus at a disadvantage.

Women's family responsibilities might be ultimately responsible for the gender pay gap but not because they limit their productivity but rather because they reduce their bargaining power with firms.

This research project will examine the role of employer wage-setting power in driving the gender pay gap in two ways. First, using data from the UK's largest longitudinal study, it will investigate the extent to which job-to-job mobility patterns differ between men and women, and whether any differences can explain the observed gender gap in pay progression.

Second, it will develop an index of employer wage-setting power based on geographical location, industry and cost of travel and test whether the index can explain gender differences in pay progression.

Tackling the gender pay gap is a widely shared goal among policy makers, political parties, women's groups, trade-unions and employer organizations. A better understanding of the factors driving the gap is essential to design effective policies. For example, in April 2017, the UK government has mandated large employers report annually on the pay gap in their organization.

If women's lower productivity is to blame for the gender pay gap, such legislation is likely to be ineffective and even counterproductive. On the other hand, mandatory reporting is likely to be more effective if employers' stronger wage-setting power is a significant factor behind the pay gap. More generally, if employers enjoy significant wage setting power relative to some of their employees, this has implications for legislation on anti-discrimination, the minimum wage, trade-unions and family policy.