Surveys can vary widely in length, from just a few questions (e.g., rate your experience and tell us why) to in-depth, advanced-methodology explorations of category behaviors and perceptions. There’s a function for all of those approaches to collecting survey data, but there are also important considerations for making sure your survey is the right length for respondents, and that they can maintain focus and provide valuable data throughout.
Length of Interview
The traditional survey guideline is to aim for up to 20 minutes to avoid dropoff and inattention. Of course, that isn’t a hard cutoff. There are some audiences, like healthcare practitioners, who are used to longer surveys - and well-compensated for their time. For general consumers, though, the average attention span isn’t getting any longer, so much shorter surveys are best to ensure quality.
An Important Consideration
But there’s also nuance to predicting how long the average respondent will take to make their way through your questionnaire. As a very general rule, respondents answer about 3 questions per minute, but this is highly dependent on the type of question. For instance, simply entering your age is much faster than thinking back on your grocery spending over the past 2 years and estimating percentages by category!
Specific types of questions that can add to length of interview, for instance:
- Open ends take more time and thought to get quality answers back.
- Numeric entry questions are faster than open text, but can lead to frustration if there is validation built in, e.g., all rows must sum to 100%, or fit within a range, or match previous responses.
- Grid questions are more efficient than asking each row as its own question, but don’t underestimate the effort, especially if there are more rows or on a mobile device.
- Ranking questions also require extra thought, especially the more items respondents are asked to rank (i.e., top 3 vs. top 5 or top 7).
This isn’t to say that these types of questions should be avoided - just that you should be aware of their implications for total length of interview.
Dialing In
Stepping back from the nuts and bolts of your survey - e.g., the number and type of questions - there are broader best practices to keep in mind when designing a questionnaire. As with many things, there’s no substitute for preparation and thinking before you act. For a survey, that often takes the form of a clearly articulated set of key questions or objectives - ideally, just 3 to 5 simple bullets. Questions that don’t fit with those topics may or may not be critical to include in your survey - especially if they add time and effort, hurt flow, and otherwise risk the quality of the data respondents provide on your most important questions.
As you work through your survey design, IntelliSurvey’s Research Services team is available to provide high-level consultation on your objectives as well as granular feedback on survey length, structure, wording, and other best practices to make sure you gain the high-quality data and insights you need. For more information, please get in touch.
