I listened to NAHT general secretary Mick Brookes telling us this morning that we could trust his members to do their own assessments of how good their own schools were, without any need for troublesome tests or pesky performance tables.
In the midst of the discussion, Mr Brookes informed us that his stance enjoyed the overwhelming backing of parents, according to an opinion poll that his union had done. Given that an independent Ipsos MORI survey for the DCSF showed a rather different result - and it was conducted using a representative sample of parents by a reputable polling company - I thought this a bit fishy.
So I checked the NAHT's website for more details of this 'poll.' In fact, there is no independent opinion poll. Instead, the NAHT has pulled together a self-selecting 'sample' of parents' views collected by NAHT members and collated with no attempt at weighting.
The press release issued in February even suggests that embarrassed NAHT press officers know the whole thing is a crock. "Whilst we recognise that this is not an independent survey, it represents a substantial body of opinion," they plead.
So, let's get this straight. The union which tells us that we can trust its members to tell parents exactly how well their child's school is doing in English and maths without independent national tests or published results is quite happy to defy the rules of statistics to get the data it wants, and to pretend that its data is of some value even though it shows results exactly the opposite of properly conducted independent research.
And we are supposed then to take their word that we don't need any independent look at how primary schools run by its members are performing?