As an empiricist it is evident that all major companies are looking for good women to join their boards.  

A very bright woman that I worked with for years recently left a major Canadian position to retire.  She has been inundated with offer to join boards, I alone have been asked for her private coordinates several times.  She is already on some boards and can join more.

It is not at the board level therefore we need to begin, but in high schools and universities, in supporting maternity leave and other women's issues.

Perhaps the number of board positions is a good long term metric of success, but let's pull women up, encourage them to take STEM courses and support them through their whole careers.