As much as we love numbers, we find ourselves often advising clients against using numeric scales in their surveys. A numeric scale is any response format that asks people to give a number within a certain range to indicate the strength of their feeling or opinion. The insanely popular survey question used to calculate Net Promoter Scores is a good example:
“How likely is it that you would recommend Acme Solutions to a friend or colleague? Please answer on a scale from zero to ten, where zero means not at all likely, five is a neutral score, and ten means extremely likely.”
There are many good reasons to use numeric scales and many types of research for which numeric scales are optimal. The NPS scale is good because it has eleven points with meaningful endpoints and a meaningful midpoint. Research shows that scales like this can be highly reliable and valid, with sufficient variability to allow for sophisticated statistical modeling.
But if your objective is to use survey data for marketing materials, public relations, news releases, or white papers, numeric scales make things difficult. They are not easy to summarize in words, and if you want to use charts that tell quick, compelling stories, you will end up having to do something like this:
A Poor Fit: Pie Charts and Numeric Scales