Quote:
Originally Posted by Carth
Brexit was just an example, many more have been wrong too . . whether that was down to polling the wrong people, poor 'pundit' interpretation, or simply bad wording in the poll itself who knows.
Suffice to say some people view polls as acceptable data, others see them as manipulation devices . . each to their own  |
Generally they’re seen as acceptable to those whose views are confirmed by them, and manipulative by those who don’t like it when the polls contradict them.
In fact, the statistical process underpinning opinion polls is very robust and their results are always delivered with caveats. It’s those who then take the results and use them for campaigning that add the veneer of either acceptability or manipulation.
For starters, there is always a margin of error. On a properly weighted sample of 1,000 this is typically +/- 3 percentage points, which from the outset should show very clearly that no poll can accurately forecast an outcome that is determined by a gap smaller than that. The Brexit referendum result was well within the polling margin of error.
Secondly, there’s the issue of properly weighting the sample. You can’t get an accurate result from interviewing the first 1,000 people you meet on the high street on a Saturday morning.* You have to have a sample that reflects the demographics of the electorate. So you have to know age/social background of your respondents. You also have to know something about their voting record on the issue at hand. That’s easier for a general election poll but next to impossible for a one-off vote like Brexit.
Again, polling experts like Prof John Curtice at Strathclyde University, who often pops up on the BBC when major voting events are afoot, are always candid about these issues. Whether they make it into the popular consciousness is another matter.
* This, incidentally, is why the “they never asked me, so they can’t be accurate in any way” objection is nonsense. You may feel like a unique individual, but at the population level you really are just a series of fairly predictable responses to major issues.
