Salary gap not simple

Behind some quite striking differences in male and female remuneration in the article on gender-based pay differences ("Women continue to earn less than men", September 29) lie a complex set of issues that was largely ignored. The factors that determine wages and salaries are many and varied. Our own university (Nottingham) was highlighted for a 10.24 per cent pay differential between male and female professors.

A similar figure was quoted in a story a year ago. The figure is based on a bald comparison of male versus female salaries without taking into consideration relevant factors such as human capital, experience, qualifications and subject area. Indeed, last year's report caused sufficient anxiety that we arranged to undertake a more systematic and comprehensive analysis of gender-based salary differences. Controlling for the diversity of factors that affect an individual's salary and trying to isolate only the gender-specific effect suggested that the real salary difference between male and female professors at Nottingham was in the region of 3-4 per cent not the 10-11 per cent you quote.

The existence of such a differential is a cause for concern, but through systematic analysis we are able to gain insights into the best strategies for addressing this situation.

Diane Birch, Christine Ennew and Jaspal Kaur
Nottingham University