As any scientist can confirm, the fact that two events repeatedly occur at the same time does not mean that one event causes the other. Trying to explain the link is often the challenge. So it is with the perennial debate over gender diversity in corporate boardrooms. As political pressure to get more women on to boards intensifies, various statistical studies – from McKinsey to Ernst & Young– have suggested that higher female representation is accompanied by better financial and stock market performance. The question is why.

Research published by the Credit Suisse Research Institute, looking at data for more than 2,300 companies worldwide, has produced an intuitively appealing explanation. First, the study notes a difference in share price returns before and after the 2008 global financial crash. For large-cap stocks, boards with female members have outperformed those without by 26 per cent during the past six years. For smaller companies, the figure is 17 per cent. In both cases the outperformance came after the 2008 ructions. The study also notes that when women are represented at board level, companies tend to have lower gearing. More than that, gearing came down faster post-2008 when female directors were present.

Wisely, the authors hesitate to draw facile conclusions and admit nothing is proved. But one explanation may be that female directors encourage risk aversion – particularly beneficial when booms turn into bleaker market conditions. If so, such a conclusion has interesting implications. For a start, it is unclear whether investors should welcome women on to company boards wholeheartedly once the business climate changes and the name of the game becomes risk-taking and growth. That said, perhaps policy makers should stuff the boards of companies that repeatedly take too many risks with female directors. A few banks spring to mind. Are there any women out there brave – and risk-averse – enough to volunteer to sit on the boards of Barclaysor UBS?