More on questions

How many questions go in a survey?

The ideal number of questions in a Kano survey depends on various factors, such as the complexity of your product or service, the purpose of your survey, and the attention span and engagement level of the survey respondents.

This being said, a typical Kano survey contains anywhere from 15 to 30 questions, but shorter or longer surveys can be effective too. It very much depends on the context. Strike a balance between obtaining enough data for meaningful analysis and not overwhelming respondents with too many questions that may result in lower response rates.

The best way to find out is by testing your survey before launching it. A small sample of respondents can help refine the survey and ensure it is well-received by the target audience.

Self-stated importance

To try and find out how important a feature is the customer, some Kano researchers add an extra question to each feature, like "How important is it or would it be if the car has good gas mileage?" (Berger, 1993). Surveyees can rate the question on a scale of 1 to 10. The researchers then use this as an extra weight in prioritising features.

Apart from the fact that "good gas mileage" is not precise and therefore not a very good question, it turns out that "Kano satisfaction scores are positively related or proportional to self-stated requirement importance (worth)" (Mkpojiogu, 2016).

We'll get to satisfaction scores when analysing survey results, but they are basically a way of reducing the results for a feature to a dissatisfaction index (a score between -1 and 0, indicating how dissatisfied a customer would be if a feature were not present) and a satisfaction index (a score between 0 and 1, indicating the satisfaction with the presence of a feature).

What Mkpojiogu's study shows is that the higher the satisfaction score or the lower the dissatisfaction score, the higher customers will rate that feature's importance.

That's why I generally don't recommend adding an extra question gauging for the self-stated importance to a survey. The less effort surveyees must spend, the better.