What is the optimal number of diagnostics in a Claims Test or Product Variant Selector?

We consider the optimal number of diagnostics from 3 to 7 questions to achieve an efficient and adequate experiment design for a Claims Test or Product Variant Selector.

For instance, suppose a claim test experiment with several numbers of claims, by default our platform shows 5 variants, then with more than 7 diagnostics; respondents are going to see 35 Likert Scale questions, that will cause fatigue on respondents and could affect results for the analysis, also respondents' experience will be affected and as a result, the rating for each claim would be less accurate. Moreover, a design with less than 3 diagnostics could limit the comprehension of preferences and insights for each claim.

For that reason, we suggest an array of diagnostic questions ranging from 3 to 7, making it easier for respondents rate statements for standard questions in the survey.