IT HAS been a turbulent few days for the BBC, Britain’s public broadcaster. On July 19th it published the names of those to whom it pays £150,000 ($195,000) or more a year. The ensuing furore was less over the level of pay, but the differences between men and women. Some female presenters discovered that they earned much less than their male peers. Of the 96 people listed, two-thirds are men; across the BBC, just over half are. In a petition, female presenters said this was evidence that women at the BBC are paid less than men “for the same work”. Although this may be true for people on the BBC’s list, it is much less clear for the rest of its 9,000 female employees: a gender pay gap at the top of an organisation does not necessarily mean that similar gaps exist at lower levels.

In Britain, as in other European countries, the average gap in pay between men and women in exactly the same jobs is tiny or non-existent, according to data for 8.7m employees worldwide gathered by Korn Ferry, a consultancy. The difference is also narrow in each of the 16 job levels in the database—except, crucially, in the highest one, in which men in some countries are indeed paid a lot more than women (see chart).

This pattern partly reflects the well-known problems that women have in advancing to senior positions, whether because of old boys’ networks or familial divisions of labour. But it is also reflective of how job markets work. For rank-and-file jobs, requirements and pay scales are largely standardised; both vacancies and candidates are plentiful. The hiring of chief executives, television stars or top footballers, however, is a different matter. These are in limited supply; paying up to outbid competitors is not unusual.

Lack of clear-cut rules and secrecy about pay for top jobs mean that candidates have lots of leeway to negotiate, says Benjamin Frost of Korn Ferry. Research shows that women do worse than men in negotiating salaries. Bias is partly to blame: surveys suggest that when women put their hands up for a promotion, they are more likely to be viewed as pushy, whereas men are viewed as ambitious. In 2014 hacked e-mails revealed that Jennifer Lawrence, an Oscar-winning actress, was paid less than her male co-stars in “American Hustle”. She later said that she had not bargained harder because of expectations to act nicely.

A new law in Britain requires all biggish employers to publish, by April 2018, data on the pay gap between their male and female employees. The reactions to the BBC’s list suggest they would be wise to break these data down for comparable jobs. That will show more precisely where the problem lies.