Writing an effective questionnaire is not a task for novices. At the very least, it requires an understanding of four basic issues:

1. Considering the differences between a questionnaire that respondents fill out themselves and one that a professional interviewer administers

2. Knowing what questions should be asked early on in the questionnaire, in the middle, and toward the end

3. Understanding how to phrase questions

4. Being sensitive to questionnaire length

Attempting to address a topic as broad as questionnaire construction in one short article—or even in two or three—borders on the absurd. There are dozens of books on the subject and thousands of technical papers. But by taking into account some of the issues noted here, and then again in subsequent articles over the next several months, you'll be able to better prepare your next questionnaire and survey.

1. Self-Administered vs. Interviewer-Administered Questionnaires

Here are some basic differences between the two types of questionnaire:

• Self-administered questionnaires should be simple, straightforward, and logical. Question 2 should follow question 1. Question 3 should follow question 2, and so forth. Moreover, the initial assumption with self-administered questionnaires should be that respondents will not complete it when there are complex skip patterns, when pages are crowded or hard to read, or when instructions for completion are overly complex.

  Some estimate that as many as 50% of respondents who start a self-administered questionnaire do not complete it because they become irritated and annoyed at the way it is constructed. When writing a self-administered questionnaire, then, every care must be taken to ensure that it is easy to complete in that it almost answers itself.

• Self-administered questionnaires should assume the respondent has an eight-grade education, whereas interviewer-administered questionnaire can be complex. Because interviewers are trained in the flow of the questionnaires that they administer and conduct practice interviews prior to confronting a respondent, a complex questionnaire that will be interviewer-administered does not pose a problem for the respondent.

• Interviewer-administered questionnaires can easily accommodate skip patterns that take a respondent from one section of the questionnaire to another based on their responses. Sometimes, particularly with face-to-face interviews, the questioning process might also involve showing respondents certain products or exhibits during the interview or having the respondents read concepts or ideas based on how they respond to various questions.

2. Knowing what questions should be asked early on in the questionnaire, in the middle, or toward the end

Questionnaires have a flow to them, usually from the general to the specific. But because the types of studies can vary so greatly, as can the goals of every questionnaire, there are no hard-and-fast rules for the flow or sequence of questions. Nevertheless, I would suggest following guidelines:

• Keep the respondent in one mindset at a time. If at all possible, complete all your questions about one topic before moving on to the next. For example, don't ask about a favorite place to shop, then about brands used and then go back to questioning on favorite places to shop.

• Ask the easy questions first. Simple questions regarding behavior, such as frequency of buying, brands purchased, or places shopped, are easy for respondents to answer because these don't require a lot of thinking or pondering. As a result, respondents quickly get comfortable with the interview.

• Place more involved or introspective questions toward the middle of the questionnaire. After the respondent is a few minutes into the interview and the easy questions are out of the way, be prepared to transition to questions that require thought and consideration. Respondents don't mind giving more thought to complex questions once they are comfortable with the interview process.

• If it's important to tell respondents who the sponsor of the study is, do so at the last possible moment. Sometimes, you'll have to identify the sponsor at the beginning, but when that's not necessary keep respondents in the dark. Once they know, their every answer will be with that knowledge in mind and will present an informed bias.

• Save sensitive questions for the end. Again, this might not always be possible, but when it doesn't matter be aware that sensitive questions can alienate respondents and turn them off to the entire interview process.

3. Understanding how to phrase questions

It takes very little thought to write out a bunch of question on a piece of paper and call it a questionnaire. It takes considerable thought to write questions that are good ones and produce a meaningful questionnaire. Consider the questions below as examples of good and bad questioning techniques:

• Biased question: What do you like about the last airline flight you took?

  An assumption here is that the respondent liked something, and so the question tends to push for a positive response.

• Unbiased question: What, if anything, do you like about the last airline flight you took?

  By your simply using "if anything" as part of the question, the respondent is not put on the spot to find something to like.

• Dual-thought question: What, if anything, do you like or dislike about your internist?

  With such a question, respondents tend to focus first on the strongest likes or dislikes. If it happens to be something they like, they will give less thought to what they might not like, and vice versa. It would be much better to ask two questions, one focusing only on likes and the other only on dislikes.

• Multiple-thought question: With 10 being more important and 1 being lest important, how important is it for a bank to have friendly and knowledgeable employees?

  Friendly is one thought, knowledgeable is another. When you ask a dual-thought question, you are stuck interpreting both issues at once. It's probably a good idea that a bank have both friendly and knowledgeable employees, but it might not be necessary. Being just the friendliest bank could set it apart, as could just being the bank with the most knowledgeable people. Keeping your questions to a single thought is most always the best approach.

4. Being sensitive to questionnaire length

Questionnaire length is dictated by the study objectives. Some questionnaires take five minutes' worth of questions to address the objectives, others take an hour. Two simple rules of thumb should be kept in mind:

1. Respondents will fill out a 40-page self-administered questionnaire if it is well written and easy to complete. They will toss a two-page questionnaire if it is cluttered and complex.

2. When conducting telephone interviews, it's relatively easy to keep respondents on the phone and answering questions for 15, 20, or 25 minutes if the questionnaire has a good flow and is thoughtfully written. But try keeping a respondent on the phone for three minutes with a questionnaire that is confusing, redundant or insensitive...

Suffice it to say that questionnaire length is less an issue than the other three that were discussed. Questioning the respondent in a professional and considerate manner is where your focus should be.