Fisking Nate Silver

The Scotsman today published an interesting interview with the American psephologist Nate Silver. Let’s have a look at the interview part of the article:

Nate Silver, the award-winning statistician who shot to fame when he correctly predicted the outcome of all 50 states in the 2012 US presidential elections, says all the indicators point towards Scots voting to stay in the UK on 18 September next year.

True, although some recent polls have been very close (37% Yes vs. 46% No in the Panelbase poll for the Sunday Times in July, and 34% Yes vs. 36% No in the indirect question asked by Panelbase for Wings over Scotland), and although the gap has been closing slowly.

Only a “major crisis” south of the Border could turn the situation in favour of independence, despite it being more than a year until polling day, he added.

If the Panelbase polls are correct, only 0.5% of Scots need to shift from No to Yes every month for the Yes side to win. That’s clearly possible without any major crisis (we’ve seen much bigger shifts than that in electoral campaigns lasting less than a month).

In an interview with The Scotsman, Mr Silver said polling data was “pretty definitive”. “There’s virtually no chance that the Yes side will win”, he said. “If you look at the polls, it’s pretty definitive really where the No side is at 60-55 per cent and Yes side is about 40 or so.

Now this is odd. To put Yes at 40% and No at 60% means he’s excluding the Don’t Knows — which is fine — but if you look at the most recent polls in that way, we get this:

Poll	Yes	No
Panelbase, WoS, August (indirect)	49%	51%
Panelbase, Sunday Times, July	45%	55%
Panelbase, Sunday Times, May	45%	55%
Ipsos MORI, Times, May	34%	66%
TNS BMRB, April	37%	63%
Panelbase, Sunday Times, March	44%	56%

I don’t know about you, but it looks to me like Nate Silver is for some reason completely ignoring the Panelbase polls in order to reach his conclusion here.

“Historically, in any Yes or No vote in a referendum, it’s actually the No side that tends to grow over time, people tend not to default to changing the status quo.

Really? Let me quote from the Wikipedia article about Quebec’s 1995 referendum: Early polls indicated that 67% of Quebecers would vote “No”, and for the first few weeks, the sovereigntist campaign led by Parizeau made little headway. […] Under Bouchard, the numbers continued to change; new polls eventually showed a majority of Quebecers intending to vote “Yes”. […] Days before the referendum, it appeared as if the sovereigntists would win.

As noted on SCOT goes POP!, there are several examples of independence referendum campaigns developing like this. He offers this explanation: My guess is that, paradoxically, the more important a referendum is, the less likely voters are to swing to No by default. The supposed tendency that Silver talks about is largely a side-effect of electorates so often being faced with relatively trivial matters in plebiscites.

“The No side is even more dominant with the younger voters, so there’s not going to be any generational thing going on.”

Really? Panelbase’s July poll had 48% Yes vs. 52% No for 18–34 year olds (after excluding the Don’t Knows), 50% Yes vs. 50% No for 35–54 year olds, and 36% Yes vs. 64% No for 55– year olds.

Most polls I’ve seen have confirmed this: The youngest voters are slightly more sceptical than those in their 30s and 40s, but the oldest voters are the ones most likely to vote No.

Speaking yesterday, Mr Silver said, however, that the Yes campaign could benefit if there is some kind of dramatic economic collapse south of the Border.

“If there was a major crisis in England – if the Eurozone split apart and there were ramifications economically (for the UK) – the maybe things would reconsidered a little bit.

Perhaps. There’s also a strand of thought that people are more likely to vote for independence if they feel positive and optimistic about the future.

But he added: “For the most part it looks like it’s a question of how much the No side will win by, not what the outcome might be.”

This is a rather bold conclusion, given the figures I quoted above.

The French-speaking province of Quebec in Canada has previously rejected a vote on independence, despite sharp “cultural differences and genuine hostility” with the wider Canadian state, Mr Silver added.

I’m not sure what he’s trying to conclude here. Surely he doesn’t believe you can only win an independence referendum if there’s sufficient “cultural differences and genuine hostility”?

“That is a case where a smaller country reads more about the economic consequences and it becomes harder to change the status quo.

As far as I’m aware, the Quebec referendums failed because they didn’t manage to convince the Anglophones they wouldn’t be discriminated against in a French-speaking country, not because they read about the economic consequences.

“That was one where the Yes vote had been ahead, then faded down the stretch and lost.

The Yes vote was well ahead until two weeks before polling day, and in the end the result was 50.58% No vs. 49.42% “Yes”. I don’t think that’s called “fading down the stretch”, it’s called “losing the final sprint”.

“So on general principle, even if you took all the undecided votes, they are more likely to end up being No votes than Yes votes.”

“On general principle”? Where did that come from? My experience from canvassing tells me that most of the undecided voters would like to vote Yes but are looking for reassurance. As a young man told me on the doorstep, after placing himself at 5 on a scale where 1 is No and 10 is Yes: “An independent Scotland could be so good!”