What was the sample size for the survey?
The more people, the better – although a small-sample scientific survey is ALWAYS better than a large-sample self-selecting survey. Note, however, that the total sample size is not always the only relevant number. For example, voting intention surveys often show figures excluding “don’t knows”, respondents considered unlikely to vote, and those who refuse to disclose their preference. While excluding these groups ensures that, the poll reports the opinion of the most relevant group – “likely voters” — reported voting-intention sample size may be significantly lower than the total sample, and the risk of sampling error therefore greater. How were those respondents chosen? Is it clear who is included in the sample and who was left out? If the poll claims to represent the public as a whole (or a significant group of the public), has the polling company employed one of the methods outlined in the questions above? If the poll was self-selecting – such as readers of a newspaper or magazine,
