How polling leads can just evaporate
The chart shows the sequence of YouGov Holyrood regional vote shares for LAB and SNP in the eleven weeks running up to the May 2011 elections.
The movement is startling and even YouGov’s eve of poll survey, with an SNP lead of just 7% was a long way out. The actual SNP lead was 18%.
This is a timely reminder for both GE2015 polling and, of course, the Scottish IndyRef, just nine months away.
We should never forget that polling can have its limitations.