Commentary
“Garbage in, garbage out” is a well-known adage that means the quality of the input determines the quality of the output in any system. For example, if a mathematical equation is improperly expressed, the answer is likely to be incorrect. The same applies to public polling. If the survey questions are vague or biased, if they are not given to a random sample of the larger population, or if they exceed the knowledge or experience level of those polled, the results are likely to be inaccurate.
These features even apply to seemingly straightforward behavioural surveys, such as election polls that ask people to choose which candidate or party they plan to support on voting day. Automated phone polls, the cheapest and most popular way such surveys are conducted, rarely ask respondents whether they plan to vote or if they are eligible to vote based on their age and citizenship….