General Tips

  1. Keep the questionnaire as short as possible. We mentioned this principle before, but it is so important it is worth repeating. More people will complete a shorter questionnaire, regardless of the interviewing method. If a question is not necessary, do not include it.
  2. Start with a Title (e.g., Leisure Activities Survey). Always include a short introduction - who you are and why you are doing the survey. If you are asking about different brands, it is often a good idea to give the name of the research company rather than the client (e.g., XYZ Research Agency rather than the manufacturer of the product/ service being surveyed). Many firms create a separate research company name (even if it is only a direct phone line to the research department) to disguise themselves. This is to avoid possible bias, since people rarely like to criticize someone to their face and are much more open to a third party.
  3. In some cases, though, it may help to mention the client. If you are surveying members of an organization, the members may be more likely to respond if they think the organization is asking their opinions on how it can best meet their needs. The same could be true when you are surveying users of a particular service.
  4. Preserve anonymity. Reassure your respondent that his or her responses will not be revealed to your client, but only combined with many others to learn about overall attitudes.
    If you hand out questionnaires on your premises, you obviously cannot remain anonymous, but keep the bias problem in mind when you consider the answers.
  5. Include a cover letter with all mail surveys. A good cover letter or invitation to take a Web page survey will increase the response rate. A bad one, or none at all, will reduce the response rate. Include the information in the preceding two paragraphs and mention the incentive (if any). Describe how to return the questionnaire. Include the name and telephone number of someone the respondent can call if they have any questions. Include instructions on how to complete the survey itself.
    The most effective cover letters and invitations include the following elements: Ask the recipient to take the survey. Explain why taking it will improve some aspect of the recipient's life (it will help improve a product, make an organization better meet their needs, make their opinions heard). Appeal to the recipient's sense of altruism ("please help"). Ask the recipient again to take the survey.
  6. Number mail questionnaires on each page and include the return address on the questionnaire itself, because pages and envelopes can be separated from each other. Envelopes should have return postage prepaid. Using a postage stamp often increases response rates, but is expensive, since you must stamp every envelope - not just the returned ones.
  7. You may want to leave a space for the respondent to add their name and title. Some people will put in their names, making it possible for you to recontact them for clarification or follow-up questions. Indicate that filling in their name is optional. If the questions are sensitive in nature, do not have a space for a name. Some people would become suspicious and not complete the survey.
  8. If the survey contains commercially sensitive material, ask a "security" question up front to find whether the respondent or any member of his family, household or any close friend works in the industry being surveyed. If so, terminate the interview immediately. They (or family or friends) may work for the company that commissioned the survey - or for a competitor. In either case, they are not representative and should be eliminated. If they work for a competitor, the nature of the questions may betray valuable secrets. The best way to ask security questions is in reverse (i.e., if you are surveying for a pharmaceutical product, phrase the question as "We want to interview people in certain industries - do you or any member of your household work in the pharmaceutical industry?). If the answer is "Yes" thank the respondent and terminate the interview. Similarly, it is best to eliminate people working in the advertising, market research or media industries, since they may work with competing companies.
  9. After the security question, start with general questions. If you want to limit the survey to users of a particular product, you may want to disguise the qualifying product. As a rule, start from general attitudes to the class of products, through brand awareness, purchase patterns, specific product usage to questions on specific problems (i.e., work from "What types of coffee have you bought in the last three months" to "Do you recall seeing a special offer on your last purchase of Brand X coffee?"). If possible put the most important questions into the first half of the survey. If a person gives up half way through, at least you have the most important information.
  10. Make sure you include all the relevant alternatives as answer choices. Leaving out a choice can give misleading results. The need to include all relevant alternatives is not limited to political polls. You can get misleading data anytime you leave out alternatives.
  11. Do not put two questions into one. Avoid questions such as "Do you buy frozen meat and frozen fish?" A "Yes" answer can mean the respondent buys meat or fish or both. Similarly with a question such as "Have you ever bought Product X and, if so, did you like it?" A "No" answer can mean "never bought" or "bought and disliked." Be as specific as possible. "Do you ever buy pasta?" can include someone who once bought some in 1990. It does not tell you whether the pasta was dried, frozen or canned and may include someone who had pasta in a restaurant. Few people can remember what they bought more than three months ago unless it was a major purchase such as an automobile or appliance.
  12. The overriding consideration in questionnaire design is to make sure your questions can accurately tell you what you want to learn. The way you phrase a question can change the answers you get. Try to make sure the wording does not favor one answer choice over another.
  13. Avoid emotionally charged words or leading questions that point towards a certain answer. You will get different answers from asking "What do you think of the XYZ proposal?" than from "What do you think of the Republican XYZ proposal?" The word "Republican" in the second question would cause some people to favor or oppose the proposal based on their feelings about Republicans, rather than about the proposal itself. It is very easy to create bias in a questionnaire. This is another good reason to test it before going ahead.
  14. If you are comparing different products to find preferences, "give each one a neutral name or reference. Do not call one "A" and the second one "B". This immediately brings images of A grades and B grades to mind, with the former being seen as superior to the latter. It is better to give each a "neutral" reference such "M" or "N" that do not have as strong a quality difference image.
  15. Avoid technical terms and acronyms, unless you are absolutely sure that respondents know they mean. If you must use an acronym, spell it out the first time it is used.
  16. Make sure your questions accept all the possible answers. A question like "Do you use regular or premium gas in your car?" does not cover all possible answers. The owner may alternate between both types. The question also ignores the possibility of diesel or electric-powered cars, and even doesn't cover the case if the person doesn't have a car.
  17. If you want only one answer from each person, ensure that the options are mutually exclusive (no intersection between the choices).
  18. Score or rating scale questions (e.g., "If '5' means very good and '1' means very poor how would rate this product?") are a particular problem. Researchers are very divided on this issue. Many surveys use a ten-point scale, but there is considerable evidence to suggest that anything over a five point scale is irrelevant. This depends partially on education. Among university graduates a ten point scale will work well. Among people with less than a high school education five points is sufficient. In some populations, a three-point scale (good/acceptable/bad) may be all some respondents can understand. Even consider not giving the possibility of a neutral position (with a scale of 4, see §20 below). Don't forget to allow the N/A (non applicable) choice if relevant.
  19. Giving a verbal or written label to each point on a scale, instead of just the endpoints, will usually yield higher-quality data, though this may not be practical when there are more than five points on the scale.
  20. Another issue on which researchers differ is whether to use a scale with an odd or even number of points. Some like to force people to give an answer that is clearly positive or negative. This can make the analysis easier. Others feel it is important to offer a neutral, middle option. Your interviewing mode can make a difference here. A good interviewer can often get an answer, but in a self-administered interview, such as a Web page survey, a person who is frustrated by being unable to give a middle answer may leave a question blank or quit the survey altogether.
  21. Be sure any rating scale labels are meaningful. For example: "best", "average" or ""worst" will force most answers into the middle category, resulting in very little usable information.
  22. If you have used a particular scale before and need to compare results, use the same scale. Four on a five-point scale is not equivalent to eight on a ten-point scale. Someone who rates an item "4" on a five-point scale might rate that item anywhere between "6" and "9" on a ten-point scale.
  23. Do not use negative numbers when asking for ratings. Some people do not like to give negative numbers as answers. A scale of -2 to +2 is mathematically equivalent to a scale of 1 to 5, but in practice you will get fewer people picking -2 or -1 than would pick 1 or 2. If you want 0 to be the midpoint of a scale when you produce reports, you can weight the answers after data collection to get that result.
  24. Always discount "favorable" answers by a significant factor. Unfortunately, there is no hard and fast rule on how much to do this. It depends on the situation. Some people tend to give answers they think will please an interviewer or even a survey company or survey sponsor, and in some cultures it might be considered impolite to give negative answers. One factor to consider is the survey mode. People tend to pick the most positive answer on a scale more often when answering telephone or in-person surveys than other types of surveys, regardless of the details of the question.
    The desire to please translates into a tendency to pick agreeing answers on agreement scales. While logically the percentage that strongly agrees that "X is good" should exactly equal the percentage that strongly disagrees that "X is bad," in the real world, this is unlikely to be true. Experiments have shown that more people will agree than disagree. One way to eliminate this problem is to ask half your respondents if they agree that "X is good" and the other half if they agree that "X is bad." You could then reverse the answers given by the second group. This is extra work, but it may be worth it if it is important to get the most accurate percentage of people who really agree with something.
  25. People sometimes give answers they feel will reflect well on them. This is a constant problem for pre-election polls. More people say they will vote than actually will vote. More people say they go to museums or libraries than actually do. This problem is most significant when your respondents are talking directly to a person. People give more honest answers when answering questions on a computer. Mail surveys are in-between.
  26. Because people like to think of themselves as normal or average, the range of answer choices you give when asking for a quantity or a frequency can affect the results. for a same value, you may make it feel more extreme if you put a s the maximum of the possible anwsers compared to another possible set of choices where that value would appear in the medium or mediu-top range.The first list of choices makes the value sound extreme, while the second list of choices makes it seem typical.
  27. In personal interviews it is vital for the Interviewer to have empathy with the Interviewee. In general, Interviewers should try to "blend" with respondents in terms of race, language, sex, age, etc. Choose your Interviewers according to the likely respondents.
  28. Leave your demographic questions (age, gender, income, education, etc.) until the end of the questionnaire. By then the interviewer should have built a rapport with the interviewee that will allow honest responses to such personal questions. Mail and Internet questionnaires should do the same, although the rapport must be built by good question design, rather than personality. Exceptions to this rule are any demographic questions that qualify someone to be included in the survey. For example, many researchers limit some surveys to people in certain age groups. These questions must come near the beginning.
  29. Do not have an interviewer ask a respondent's gender, unless they really have no idea. Have the interviewer fill in the answer themselves.
  30. Paper questionnaires requiring text answers, should always leave sufficient space for handwritten answers. Lines should be about half-an-inch (one cm.) apart. The number of lines you should have depends on the question. Three to five lines are average.
  31. Leave a space at the end of a questionnaire entitled "Other Comments". Sometimes respondents offer casual remarks that are worth their weight in gold and cover some area you did not think of, but which respondents consider critical. Many products have a wide range of secondary uses that the manufacturer knows nothing about but which could provide a valuable source of extra sales if approached properly. In one third world market, a major factor in the sale of candles was the ability to use the spent wax as floor polish - but the manufacturer only discovered this by a chance remark.
  32. Always consider the layout of your questionnaire. This is especially important on paper, computer direct and Internet surveys. You want to make it attractive, easy to understand and easy to complete. If you are creating a paper survey, you also want to make it easy for your data entry personnel.
    Try to keep your answer spaces in a straight line, either horizontally or vertically. A single answer choice on each line is best. Eye tracking studies show the best place to use for answer spaces is the right hand edge of the page. It is much easier for a field worker or respondent to follow a logical flow across or down a page. Using the right edge is also easiest for data entry.
  33. The choose a survey system which let you create a Questionnaire Form with the answer choices in two columns. Creating the form that way can save a lot of paper or screen space, but you should recognize doing so makes the questionnaire a little harder to complete. It also slows the data entry process when working with paper questionnaires.
  34. Questions and answer choice grids. They can look attractive and save paper, or computer screen space. They also can avoid a long series of very repetitive question and answer choice lists. Unfortunately, they also are a bit harder than the repeated lists for some people to understand. As always, consider whom you are studying when you create your questionnaire.
  35. When using a grid, the way you lay out the choices will affect the results. It is not clear whether it is always best to make the leftmost column the most positive response or the most negative response, but there is a tendency for people to pick the left side of the grid more than the right side, regardless of whether the left side is positive or negative. So any time you use a grid you should discount the left side responses to some degree. This tendency does not interfere with comparing the answers in different rows in the grid, but does affect absolute statements of a line of the grid.