A lone woman to a board is most definitely not 'job done' on diversity
The study by Ann Owen, Professor of Economics at Hamilton College and Judit Temesvary, a Senior Economist at the Federal Reserve Board of Governors looked at the company boards of US holding banks. They found that:
"gender diversity has a positive impact on various measures of performance, once a threshold of diversity is achieved."
In fact, the evidence showed a low level of diversity can adversely affect performance measures. Owen and Temesvary's other key finding was that benefits of diversity on boards only accrued when the bank and board were well managed (which they assessed by the bank being well capitalised).
It offers some clear evidence that appointing a lone woman to a board is most definitely not 'job done' on diversity.
I believe this to be a very useful data-driven piece of research, particularly for the financial services sector which is currently under the regulator spotlight with regard to culture. The study confirms the validity of the regulator's focus on diversity as the data shows banks with gender diverse boards had fewer regulator interventions, an effect that was magnified during the financial crisis.
In short, this is yet more robust evidence showing that well managed diverse teams help improve the culture of a company and lead to better decision making.