The push for board quotas in the EU has been relatively successful. Ten countries have signed on, and the gender balance on these countries’ boards has improved significantly. However, much of the improvement has come from the addition of women as non-executive board members, the trickle down effect on executive teams has not been obvious, and the benefits remain hotly debated. Key countries, like the US and the UK, are unlikely to adopt similar measures. Still other countries have adopted voluntary targets, with mixed results. (Here’s a complete overview of the board situation.)

The challenge is that adding a few non-execs to your board is proving a lot easier than balancing your leadership teams. Recently Google has led Silicon Valley companies in a collective and public recognition that their gender balance is not satisfactory, and published some aggregate statistics. The corporate world is gradually responding to the pressure for greater transparency on their internal reality, which up to now has been jealously guarded. It would help to come clean, so that we can really compare companies and countries.

Rather than legislating quotas, why not require the publication of companies’ gender statistics beyond their highly visible boards? Such transparency would allow everyone from talented graduates to savvy investors to see which companies are truly – and sustainably – balancing their senior leadership ranks. And it would allow men and women who want to work for or invest in balanced companies to be able to identify them. What company will be credibly able to argue against transparency?

Google said it best: “It is hard to address these kinds of challenges if you’re not prepared to discuss them openly, and with the facts.” We need better, more specific data – not just aggregate statistics on whether companies have any women in management, or a certain percentage of female employees. Such broad datasets obscure the important question of how many companies manage to balance their senior leadership teams, and by how much.

Let’s keep things simple. For our initial purpose, let’s focus on the top. To keep it easily comparable and implementable across companies, let’s stick to the top: publish, in the annual report, gender balance statistics for the top three levels: the CEO, the CEO’s team, and that team’s direct reports.

While some may argue that this is a limited view, we’d suggest it is far more representative than the board, and represents the reality of decades of corporate efforts (or lack thereof) to improve the balance of the sexes. Let’s also measure whether the leaders in question are in support functions or operational roles. And while we’re at it, why not make it a global metric? Why not get a few key names and institutions to align behind the idea and push it?

This would be enough to raise the pressure and the visibility of what companies have achieved with their efforts and initiatives. It would reward the best companies and employers with enhanced visibility and encourage the rest to balance. It would enable researchers everywhere to analyze what really works – and what doesn’t. It would allow the world’s best talent to choose to work in more progressive and balanced environments.

Although I’ve tried to keep this simple, I know how difficult it will be.

We have carried out research on executive teams for the past five years with our Global Gender Balance Scorecard. We know just how hard it is to come up with comparable results, even with our limited focus on the top two levels. So many companies hide the reality of their unbalanced top teams behind impossibly large “leadership teams.”

The UK and Australia have both been pushing for clearer reporting. The UK’s Think, Act, Report initiative is a good model, which some 200 companies have signed up to. The issue seems to be that they may not all be reporting exactly the same thing, or the key levels that we will be interested in: the top teams.

Australia has focused on analyzing just the top three levels of management (Key Management Positions or KMPs) in their newly introduced Gender Equality Scorecard and the results are very clear. “Women comprise 26.2% of the top three layers of management. Employers are failing to take a strategic whole of enterprise approach to gender equality; only 7.1% have a standalone overall gender equality strategy. And a third of companies have no female KMPs at all.”

The US has a variety of initiatives, like The Chicago Network’s survey of the city’s 50 listed companies. Since 1998, this analysis has tracked the gender balance on the board and among “top earners.” This year’s study reveals that more than 25% of top earners are female at only four companies. At two-thirds of the companies in the study, no top earners were female.

But none of these studies are sufficient to help women easily see which companies value them – and which don’t.

The simple metric I’ve proposed here could be a precursor to the spread of more detailed national reporting requirements. Such reporting should be voluntary at first. Start by inviting all the big publicly listed companies (Fortune 100, FTSE 100, CAC 40, DAX 30, and so on) in each key market to submit their data (we already report on their data on the level reporting in to the global CEO). Also publish the list of companies that have not provided their data. Once the survey gets established, propose it to governments as a legislative requirement in annual reporting. The objective is to create a very simple global index that will get CEOs competing on their gender ranking. That’s when CEOs will start getting serious about sex.