Don’t Know Is Not an Option
A perennial debate among survey researchers is whether respondents should be allowed to answer “don’t know” or “not sure.” In fact, this is something we at Versta Research wrestle with (and argue about) internally almost every day.
My approach is generally to not allow them. We have seen strong evidence in our own work that a large majority of don’t-know responses reflect an unwillingness of respondents, not an uncertainty. This is borne out by a larger body of literature on survey research. Professor Jon Krosnik, a top expert on survey methods at Stanford University, has written (way back in 2002):
“Many people who report attitudes in surveys do not have deeply rooted preferences that shape their thinking and behavior. But offering a no-opinion response option does not seem to be an effective way to prevent reporting of weak opinions. In fact, because many real attitudes are apparently missed by offering such options, it seems unwise to use them. This is because the vast majority of NO responses are not due to completely lacking an attitude and instead result from a decision not to do the cognitive work necessary to report it.”
Of course this does not apply to questions for which respondents may truly have no basis for answering. So we must carefully think through every question and decide whether don’t-know is reasonable, or just a lazy response. There is also a risk that requiring substantive responses will turn away respondents who are otherwise willing to help. If those respondents are your customers, at least you should let them skip questions if they want.
So here is our approach and a general set of recommendations:
- If the survey is fielded among research panelists, or if respondents are being paid to provide input, require an answer to every question and avoid don’t-know options except on specific questions where “not knowing” makes good sense.
- If the survey is among your own customers who are simply offering the favor of their input, allow them to skip questions, but do it without calling attention to that as an option. Offer don’t-know options only on specific questions where “not knowing” makes good sense.
Still not sure of the best approach for your research? We are always happy to give you our best advice and to share our expertise. Give us a call at 312-348-6089 for help.