Useful market research rules of thumb
Sometimes it’s helpful to estimate the length of a survey before it has been programmed. As a rule of thumb 1 minute per typed page for an online survey is a good start, for telephone research studies multiply by 1.5 (and for translation to German multiply by 1.25!).
If you want to get a little more technical… on average respondents can answer 5.5 questions per minute. So, you can simply tally up the questions and divide by 5.5. But NO CHEATING! Remember to include all the screening and profiling questions, count each brand assessed against a battery of statements as a single question, add an extra “question” count for every concept or lengthy instruction to be read and consider every open-ended question as equating to two questions (they really do take twice as long).
If you need to reduce length, then it pays to revisit the number and format of the questions with an eye on opportunities to simplify and maximize the ease of the exercise for research participants. Remember that “hard” questions such as those involving calculations or perhaps requiring respondents to provide information in unfamiliar ways will take longer.
When it comes to qualitative depth interviews allow 12-15minutes per page of A4 in a developed topic guide. But note that a topic guide is not simply a list of questions, a good guide provides an experienced interviewer with the general flow and content to cover. They will use the guide to manage the discussion to feel natural and conversational. Don’t forget that the warm-up section at the beginning is critical to set the scene, establish rapport and ensure that the rest of the interview is optimised for success.
A qualitative researcher will also build understanding through non-verbal cues. As a result, the best interviews are those that can take place in person. This also allows for genuine interaction with material you may wish to explore. The increasing prominence of Zoom and Teams means that many interviews now take place virtually. This can be a much more cost-effective option albeit It is still important to “see” the respondent so we always recommend that cameras are on.