Matrix Questions: Powerful but Perilous Technique
Posted by Jeffrey Henning on Thu, Apr 23, 2009
The four basic question types can be combined into matrix questions, as in the following example, which asks the respondent to rate satisfaction with their current electronics, their likelihood to purchase a replacement in the next half year and the brands they are considering for a replacement:
This is a concise technique for combining questions with common topics and can be 50% faster for the respondent to complete than having to answer each question separately. No wonder survey authors love them.
Unfortunately, matrix questions do raise a number of issues:
- The faster speed of completion may lead to errors.
- Respondents can be prone to "straightline" their answers to matrix questions, selecting the same choice for each respondent, in a virtual straight line down the grid.
- Splitting the matrix into its component questions has greater predictive validity according to SSI's report "Grid Test Summary" (March 2009), perhaps precisely because doing so does take respondents more time to answer each question.
Use care when using matrix questions in your surveys.
When do you think matrices are the most appropriate way to ask for information?