You might remember that Hamish Allan was one of two Facebook users who successfully demanded that a post be edited to remove commentary which dared to dissent from the gospel of "tactical voting on the list". He actually turned up here eventually, and I had a long exchange with him, but it's probably gone largely unnoticed because it was on an old thread (in fact two old threads). Given that this is a person who presented himself as an authority on why the views I have been putting forward on the subject are not merely open to question, but are actually provably, factually wrong, I was absolutely flabbergasted to discover just how weak his own counter-arguments were. By the end, I realised that he didn't even seem to understand how basic arithmetic works. It's pretty frightening that such a person successfully managed to shout down dissenters on the Facebook thread, and seemingly convinced a decent number of people that his "tactical voting" theory was perfectly sound.
1) First of all he argued that it was unreasonable for me to make the point that achieving a sufficiently large tactical switch to the Greens was unrealistic, given that one of my own assumptions was also "completely unrealistic" - namely that it was possible that six constituency seats predicted to be won by the SNP could instead flip to Labour, thereby meaning that the SNP would suddenly desperately need votes on the list that had "tactically" switched to the Greens. But anyone who thinks that's unrealistic simply doesn't understand the nature of winner-takes-all constituency elections. The scenario I painted was very specific - in all six seats, the SNP were predicted to lead Labour by 4% or less. That means all of those seats were on a knife-edge, and could easily be won by either party. There is absolutely no inhibiting factor that would prevent all six being won by Labour - it would simply require the prediction to be slightly out (due to polling inaccuracy of the sort we saw last month), or for there to be a small late swing.
2) He then argued that there is no constituency seat at all in Scotland that is too close to call - ie. his tactical voting strategy rests on the expectation of the SNP capturing every single Labour constituency seat. In a spectacularly ill-judged attempt to prove he was serious about this, he offered me an even money bet that Labour would win any constituency of my choice. Those of you who understand betting odds will already be rolling about on the floor laughing at this point - because what he was effectively saying is that he thinks there's at least a 50/50 chance that Labour will lose any seat I care to mention. Wow. That's his notion of "certainty", and that's the basis on which we are being invited to gamble on his "strategy".
3) When I pointed out to him that "too close to call" has a rather broader meaning than "a 50/50 chance", and that American TV networks would never "call" an election until they had more than 99% certainty of the outcome, he reacted with utter incredulity. Was I really saying that if one presidential candidate had an 89% probability of winning, the networks would still describe that as too close to call? Yes, of course that's what I was saying. An 11% chance that the other guy will win is extremely significant. Put it this way - if I could demonstrate to you that there is an 11% chance that your house will be flattened tomorrow by a hurricane, would you be concerned or unconcerned? Yeah, exactly.
This is where the tactical voting theory falls apart. It rests to a very large extent on an assumption of the SNP winning every single constituency seat in an electoral region, which means - just for starters - that you need to have advance knowledge of the result in eight, nine or ten completely separate elections. It really isn't good enough for someone like Hamish Allan to casually tell you that there is only an 11% risk of the SNP failing to take this seat or that seat - because if that's the average risk in each of nine seats, the cumulative risk that the SNP will fail to take at least one is much higher.
4) Here we come to the bit where I realised that Hamish doesn't understand basic arithmetic. Because I'd pointed out that he couldn't demonstrate 99% certainty that Labour would fail to win each individual seat, he apparently thought that was tantamount to me saying that I was 99% certain that Labour would take at least one seat, and challenged me to give him odds of 99-1 against that failing to happen. He would put down a £10 stake, and I would give him £1000 if he won. That's the rough equivalent of telling me that because I think there's at least a 1% chance of the Greens winning Glasgow Kelvin, I must be saying there's a 99% chance of the Greens winning at least one constituency seat in Scotland.
I actually asked him whether he was on drugs at that point. I really don't want to spend the next eleven months having a never-ending, soul-destroying argument with this sort of innumerate idiocy, but it's difficult to move on for as long as people like Hamish are still peddling it, and are attempting to shout down anyone who dissents. I couldn't help but be amused by the glorious irony of the most recent public post on Hamish's Facebook page -
"I do not wish to live in a world in which people have a right not to have their ideas challenged."