Up the poll?

How much should we read into today’s Populus poll in The Times, which shows the Lib Dems on 19 per cent (up 3 per cent)?

Not much.

Populus suveys of this type usually have 1,500 respondents, which gives a margin of error around plus or minus 3 per cent. In other words, the Lib Dems could still be on 16 per cent, or perhaps up at 22 per cent! That, and the fact that polls are time specific, means that we really need to look at the trends in Populus and all the polls, probably over six months. But the media’s judgements will be well-formed in about three months’ time.

According to John Curtice’s “poll of polls”, the Lib Dems were on an average 16 per cent rating last year, compared to a national vote just under 23 per cent at the 2005 general election. I think that an average score of around 20 per cent over six months will be the generally accepted, minimum test of “success” or “failure” for the Lib Dems under the new leadership.

And how do we judge whether Nick Clegg has “succeeded” or “failed” as leader; the extent to which he is driving the party’s poll fortunes?

Not by looking at one poll, especially not today’s.

The Populus leader index measures “how good a leader”, on a 10-point scale. As Peter Riddell comments today:

“Despite the rise in Lib Dem support, the key finding for Mr Clegg is that about two fifths of voters do not yet know enough about him to take a clear view (compared with only 9 per cent for Mr Cameron and 5 per cent for Mr Brown). That is why not too much should be read into his initial leader index of 4.40, fractionally above the last one for Sir Menzies Campbell. But Mr Clegg’s rating among Lib Dem supporters of 6.5 is well above his precedessor’s last one of 5.63 in July. Mr Clegg’s ratings on leader attributes are below Sir Menzies’s but, again, up to a half of voters are don’t knows.”

Again, we will need to look at the trends over the coming months. Charles Kennedy’s highest rating was 5.18 (October 2003). His lowest was 4.68 (February 2004). Ming Campbell’s highest rating was 4.70 (May 2006) and his lowest 4.20 (May 2007). So I think that commentators will expect Nick Clegg to be scoring at least 4.90 (and, with Lib Dem voters near to Charles Kennedy’s rating of 6.55 just before he quit), with the number of “don’t knows” slashed right back, by party conference time.

Also, YouGov, ICM and Ipsos-MORI ask for job satisfaction ratings for each leader and these are documented on the very useful UK Polling Report website. Charles Kennedy’s did not go below +8 per cent (MORI, Feb 2005) and, at the start of the last election campaign, went up to +35 per cent (YouGov). Ming Campbell’s were usually in negative, single figures and, according to YouGov, finished in the negative 20s. I expect the commentators to quickly set a bar for Nick Clegg to usually hit double-digit, positive figures.