The Fawcett Society tells us that yesterday, Thursday, was Equal Pay Day. Women earn, on average, less than men, therefore women will be working for the rest of the year for free.

Women will in effect work for free for the rest of the year because of the gender pay gap, which will take 60 years to close at the current rate of progress, campaigners say.

The Fawcett Society called for more action from the government and employers to tackle pay discrimination, job “segregation” and help women into senior posts.

Thursday has been labelled equal pay day (EPD), with the society saying the 13.9% pay gap means women are in effect working for nothing from now until the end of the year.

There is a problem with this calculation. Their basis is this:

EPD is calculated using the mean full time gender pay gap , which is currently 13.9%.

We have been through this a number of times over the years. Sir Michael Scholar, of the UK Statistics Authority, was most insistent upon the point in a couple of letters.

We must, when discussing this point, use the median full time pay gap, not the mean. That median is currently some 9.6% or so.

What this means is that the Fawcett Society is protesting on the wrong damn day. This is quite apart from the fact that the remnant pay gap is about the choices made by parents over who is the primary child carer and pretty much nothing else.