How Are Questionnaires
The questionnaire is the main data-collection device in a poll or survey. You can think of it as the "vehicle" for gathering information from survey respondents. It serves the same function that an electron microscope does for a biochemist or a powerful telescope for an astronomer. For this reason, many survey researchers refer to the questionnaire as the instrument.
Each questionnaire consists of a number of questions. These are the specific tools that pollsters use to take their measurements. Regardless of whether people are surveyed via mail, telephone, the Internet, or in person, it is the individual survey question that is the source of the data that pollsters later analyze.
Pollsters often refer to these questions as the items in a questionnaire. Election poll questionnaires typically include items that measure people's opinions; knowledge of candidates and issues; voting intentions in forthcoming primaries or elections; whether and how they voted in past elections; and background demographics such as gender, age, education, and party identification.
The quality of the data collected in a poll can be a function of which questions are asked, how the individual questions are worded, how the respondent is allowed to answer to the questions, and even the order in which they are asked. The details of these issues and the results of some research on their effects are summarized in the answers to the following questions.