Could the battle be closer than the headline gap of 14%?
I’ve now had chance to examine the detailed data from the weekend’s ICM poll on Glasgow East and there are elements which suggest that it might be better for the SNP than the headline data suggests.
Spiral of silence adjustment. The actual shares in the poll before the final adjustment were LAB 46%: SNP 35%: CON 7%: LD 10%. The published figures were L47-SNP33-LD9-C7. The change, like with all ICM voting intention polls, was based by adding half those who said they were voting but would not express an opinion in line with what they did at the general election. At Crewe & Nantwich ICM’s pre-adjusted figures proved to be much closer to the actual result.
Voting certainty adjustments. A total of 79% of those saying they would vote Labour said they 10/10 or 9/10 on the certain to vote question. The SNP proportion was 66%. This is quite unusual for generally Labour supporters are less certain. This does suggest that the SNP might be able to narrower the gap with an effecting GOTV operation.
Past vote weighting adjustment. There was a surprisingly large past vote weighting adjustment that scaled back the views of those who said they voted SNP in 2005 by more than a third. Normally the party support that has to be most scaled back is Labour.
ICM are operating in line with their normal procedures and we should not read too much into this. But I do think that the “spiral of silence” approach might not be so valid in by elections.
At 2/1 in the betting the SNP is starting to look good value.