Street interview: the most unreliable reference

From TV programmes and some online media, we often see there are many street interviews which are used to support the media’s opinions or observations. Then here comes a question that how reliable these street interviews are.

My answer to this question is that street interviews are the most unreliable sources that you can trust. The major reason is street interviews have serious selection bias issues. Firstly, the population who are willing to answer street interviews, particularly those involve very sensitive questions, share similar characteristics; therefore, the interviewees are not randomly selected, the results generated by street interviews cannot reliably reflect the entire population’s opinions. Secondly, the interviewers usually conduct street interviews within limited regions due to cost concerns and other constraints, so the sample is selected based on their geographical characters. Thirdly, we do not know whether we watch all conducted street interviews or a selected sample of street interviews, and the media does not tell us either.

Moreover, many studies have found that the ways to answer questions can largely influence the interviewees’ answers to the questions. Therefore, it is possible for interviewers to design their questions to ensure they are more likely to get the answers they want. 

Since street interviews are so unreliable, when we are watching those, we should ignore the messages they send and focus on the data coming from a much larger and randomly selected sample.