With the narrowing of opinion polls recently in the UK General election, I think people need to question what they actually show.
An opinion poll of voting preference is not simply asking 20 people (or 200 or even 2000) people what they think and then publishing the results.
They are a lot more involved than that and depending on the assumptions used the results can vary greatly.
Firstly a simple example.
To simplily matters and ignore opinion, consider an election on a factual basis where a person would vote whether they are old or young. Based on the criteris there are 20 participants that can vote – 10 old people and 10 young people