The simplest questionnaire gathers some form of demographic information. This is factual information that gives you more detail about a particular subject you are studying. An employment application is a good example of a demographic questionnaire. It largely gives a more well-rounded look at who the person is you are going to interview. It also shows the dangers of even such a simple questionnaire --- it depends on the reliability of the person self-reporting the information. A questionnaire is always a start to research, never an end. Each item must be checked for accuracy to ensure you get good information to work with.
An interactive questionnaire invites fuller responses from the subject by using open-ended questions in an effort to begin a dialogue. It does not simply ask for demographic information. A candidate for public office in a small district can make effective use of an interactive questionnaire by taking several key issues and asking how the people he surveys thinks those issues should be addressed. When he examines the answers, he will find common threads that run through the answers, which can tip him off to themes that are prevalent in people's minds, but not obvious until asked. He can even ask what local issues are important and why. Even answers that are outliers open up an opportunity for informed dialogue with the respondent.
Poll questionnaires often used --- and misused --- by candidates for public office. By formulating questions related to issues you know are controversial, you can get a good sense of where the public in your district leans on those issues. This can be dangerous, though, because the temptation is to word the questions in a way that suggests your preferred answers. When you do so, you get a false picture of what the public thinks and make bad decisions based on that faulty information. For example, if your local school has low testing scores, you might form a questionnaire that notes this and then asks if you should spend more on education. But such a question leaves only two choices and implies that there is only one solution. It is far better to start with an interactive questionnaire that solicits ideas, then follow up with a poll questionnaire that gives a range of those ideas as possible responses. This will give you a truer sense of the pulse of your district.
High school and college reunion committees often make use of entertaining questionnaires that show the contrast between what alumni were doing and what they are doing now. Questionnaires on favorite foods, television shows and actors and actresses can be both fun and revealing. They also can show hidden patterns when unconnected items are compared in large groups. In fact, that technique is used by many mass marketing firms. Surveys can reveal that people of particular political persuasions prefer one type of store to another, or one type of soft drink to another or even one actress in a television show to another in that same show. Using that information, these companies will sometimes use the information they have gleaned to reach that particular political demographic without making it obvious that they are doing so. For example, if you found that 70 percent of self-reported conservatives preferred a particular brand of cola, you could make a very effective appeal to people who bought that brand of cola without revealing you were actually making a pitch to political conservatives.