The art of questionnaire design is full of so many minute details, especially for designing rating scales. The considerations for ratings questions are as normative as they are numerous: how many ratings points to use? Even or odd number of points? Balanced or unbalanced scale? Forced or unforced choice? There are many options, and many researchers default to a five or 10-point rating scale just out of rote or past experience. A poorly – or overly painstakingly – chosen rating scale can lead to biased responses, respondent fatigue and abandonment, and useless results. When deciding on what rating scales to use, it is most important to consider first who your respondents are.
How Many Points?
The number of points to use in a rating scale can be challenging. Use too few points, and you may not get much precise data; use too many, and you may confuse or tire your respondents. Just how many points are appropriate depends on your audience. If your respondents are likely to skew either heavily positive or heavily negative, then you might want to opt for more points, like a seven to 10-point scale. This is because people who are generally positive (or negative) toward your company or product can have different intensities in their attitudes and agreements.
Let’s assume a professional association conducts a survey of its members and asks the question “Overall, how satisfied are you with your membership in our organization?” Consider a five-point scale below:
Generally, if 80% of the association’s members were either “satisfied” or “very satisfied,” it’s really of no value to the association. There’s no way to gauge the intensity of their satisfaction. But, if the association were to use a nine-point scale like this one:
Then those 80% of satisfied members will be more spread out in terms of their satisfaction. For example, if 80% of respondents give a score greater than 5, but only 10% give a score of 9, then the association has an approximation of its hardest core supporters, and then has a better idea of how fluid member satisfaction is. It can then focus on developing programs that graduate members from the six to eight ratings towards a nine.
Also, the lengthier scale can be useful if you’re using this question’s responses as a dependent variable when performing regression analysis, using the responses of other questions to predict responses to this question. These options are not available with the five-point scale. Of course, a seven-point scale might be used instead of a nine-point, depending on the degree of skewness in responses.
How do you Determine the Degree of Respondent Skewness Before Administering the Survey?
It can be hard to know in advance how respondents will rate and whether the ratings will be normally distributed or skewed. There are two ways to find out: past surveys and pilot surveys.
If the association has conducted this membership satisfaction survey in the past, it might see how respondents have traditionally fallen. If responses have generally been normally distributed, and the association has been using a five-point scale, then the association might want to stay the course.
On the other hand, if the association finds that past surveys are falling lopsidedly on one side of the five-point survey, then it might want to consider increasing the length of the scale. Or, if the association was using a seven or nine-point scale previously and finding sparse responses on both ends (because of the wide lengths), it may choose to collapse the scales down to five points.
Making changes to survey scales based on past survey responses can be problematic, however, if the past surveys are used for benchmarking. Care must be exercised to ensure that the results of the modified scale are easily translatable or imputable to the results of the past survey scales, so that comparability is maintained.
The association can also use a pilot survey as a litmus test for the spread among respondent opinion. If the association is unsure how members will score on certain rating questions, it might send out two or three versions of the same questions to a very small sample of its membership, one testing a five-point, another a seven-point, and the other a nine-point. If results come back with a normal distribution on the five-point, and more sparse and spread out on the seven and nine point scales, then the association knows that a five-point scale is appropriate.
If, on the other hand, the association notices concentration on one end of the scale for all three versions, then it can look at the seven and the nine-point tests. If it sees more sparseness in the nine-point scale, then it may opt for the seven-point scale. Otherwise, it may choose to go with the nine-point scale.
Of course, for the pilot survey to work, each member of the association must have an equal chance of selection. Of those members who do receive the pilot survey, each must also have an equal chance of getting one of the three versions. This ensures a random probability sample which can be generalized to the association’s full membership base.
As you can see, there are lots of considerations involved in constructing a rating scale question. In tomorrow’s blog post, we’ll discuss whether it’s best to use an even or odd number of points, and hence, forced and unforced choices.
Let Analysights Take the Pain out of Survey Design!
Rating scales are but one of the important things you need to consider when designing an effective survey. If you need to design a survey that gets to the heart of what you need to know in order for your company to achieve marketing success, call on Analysights. We will take the drudgery out of designing your survey, so you can concentrate on running your business. Check out our Web site or call (847) 895-2565.
Tags: 5-point scale, 7-point scale, 9-point scale, Analysights, five-point scale, likert scale, market research, marketing research, nine-point scale, pilot survey, rating scales, respondents, seven-point scale, skewness, survey, survey research, survey respondents, Surveys