I gave evidence yesterday to the Speakers Conference on increasing diversity in Parliament, having made a written submission, drawing on the research into candidate selection published by the Fabian Society last November.
While people can legitimately disagree about what should be done, we should be able to agree on what the facts are.
I concluded that most public and political debate is rather too complacent about progress being made on gender, and too pessimistic in failing to recognise the scale of progress being made on race.
The prevailing mood of pessimism was reflected in questioning from Parmjit Dhanda MP: he said he had changed his mind to favour all black shortlists because he feared that it would take most of the century to achieve change otherwise.
The most popular soundbite in the debate - that we should not be prepared to wait 75 years for a representative Parliament - was also put to me by David Lammy an ippr podcast published today.
He is far from alone. This was the headline claim of Operation Black Vote's report to Harriet Harman and the government equalities office; Trevor Phillips endorsed it in his evidence to the Speakers Conference; Keith Vaz, who chairs Labour's ethnic minorities taskforce told Parliament this showed why change was needed.
But it isn't true.
I was able to give the Speakers Conference the good news that current progress is much faster - probably three times faster - than is being claimed by the most prominent public advocates in this debate.
Why is the '75 years' claim calculated?
The 75 year claim is simply based on observing that there were four black and Asian MPs in 1987 and fifteen in 2005. An increase of "two and a half MPs per Parliament" is therefore projected forward across the next fifteen Parliaments.
Leaving aside the excessive simplicity of a linear projection of this kind, we can now see how much this underestimates the current rate of progress.
A "75 years" wait depends on the prediction that 'current trends' will give us 17 or 18 BME MPs at the forthcoming election, and that we won't see 25 black and Asian MPs for another four General Elections.
The 75 years trajectory
2005: 15 MPs now
2010: 17-18 at the next election
2014/15: 20 after two more general elections
2019/20: 22-23 after three general elections
2024/25: 25 after four general elections
2028/29: 27-28 after five general elections
And so ploddingly on ...
The good news on BME selections
Fortunately, in the real world, we are doing much better than this gloomy prognosis. At the next election, we should see a rate of progress three times faster that this. I expect to see those making this claim knocking around 50 years off the 75 year projection before this time next year.
I don't think the headline number of MPs is as important as achieving fair chances and no unfair barriers for candidates. I think it is safe to make a (rather cautious) prediction of a net gain of seven BME MPs at the next General Election, to take the total to 22 in 2010, based on the selections which have already taken place. Interestingly - perhaps surprisingly - there are likely to be 22 BME MPs (at least, and perhaps slightly more) whatever happens politically. I will come back to that in another post.
The Speakers Conference has today published an interim paper which stresses that the parties have a good chance to speed up change. The final total could be higher.
For now, I would suggest that those interested in an evidence-based debate should quietly retire the claim about a 75 years wait for a representative Parliament.
While so much of the debate lags behind the evidence, many of those who champion more BME representation are currently telling the candidates of the future that their chances are much much gloomier than is in fact the case.