As always, the first and best advice with regard to polls is what it always has been: Never put to much emphasis on single polls. If a poll goes against the trend, the likelihood that it is an outlier is pretty big – especially given the high number of polls we get these days. Needless to say, this goes against against the journalistic rule of thumb that outliers and apparent trend-breaks should be reported as loudly as possible.
My best word of advice is to check Berlingske’s Barometer which is a weighed average of polls.
Anyway, we have some interesting results after the summer break: The trend still is that the left side (including the Social Liberal Party) is leading, but Gallup deviates but having a much smaller lead for the Social Democrats and the left in general, while Altinget’s pollster gives the SLP a relatively disappointing 5,1% of the vote in its latest poll. Here, we should remember that Altinget only has one poll to point to.
I can’t say what is going on, but it would be interesting to know how Gallup and the other polling agencies have arrived at their results. I assume that the weighing of the raw data plays a role here.
If I should stick my head out, I would be sceptical of claims that the Social Democratic lead could vapourise during the eventual election campaign. It is true that the Social Democrats managed to overcome an almost certain lead for the Liberals in the 1998 election and that the Social Democratic performance collapsed during the 2005 campaign. On the other hand, the economic background for the government was more positive both years.