A questionnaire is a useful tool for gathering information in face-to-face, postal mail, email and telephone settings. The questionnaire should focus on specific aims and objectives, including asking and collecting the right type of information and making sure each question is specific, objective and understandable.

Ask the Right Types of Questions

Above all, a questionnaire should assist in accomplishing the research objective. Options such as multiple-choice questions, questions that use a rating or ranking scale and closed-ended questions will produce different types of responses. Multiple-choice questions and questions that use a rating scale are useful for gathering information about preferences, attitudes, opinions and behavior. Closed-ended questions help you gathering demographic and other fact-based information you can then use to classify people or situations.

Quantitative vs. Qualitative Information

Although you can use a questionnaire to collect both facts and subjective opinions, according to the Food and Agriculture Organization of the United Nations, a questionnaire whose objective is to collect facts is often more useful. That's because conciseness and specificity are questionnaire development best practices. Conciseness requires that you focus on gathering only essential data, while specificity requires that the data you collect meet a particular research objective. Subjective questions not only can add length, but they also introduce irrelevant data into the results.

Be Objective and Unbiased

According to James P. Key, a professor at Oklahoma State University, a well-written questionnaire aims for objectivity. It does not include leading questions that suggest a desired response. For example, the question “Do you agree with consumer research experts who say that buyers should comparison shop” could sway the answer a participant gives. A well-written questionnaire also does not introduce bias by tailoring response options. For instance, a question about customer satisfaction that has a very satisfied, satisfied and dissatisfied option is biased toward getting a positive response.

Gather Complete and Accurate Information

A questionnaire should aim to gather complete and accurate information. Key says a questionnaire designer should focus on writing clearly worded questions using natural and familiar language that respondents fully understand. And she should provide any background a respondent might require to answer a question. For example, you might tell the respondent the hours the customer service department is open before asking whether the customer service department maintains convenient hours. This can help you avoid participants refusing to answer, answering a question they do not understand or lying to the interviewer.