We are making a simple Likert scale radio group for feedback and will group it as follows:
Please rate the service you received:
- Very poor
- Very good
According to usability guru Jakob Neilsen, radio choices should have one option selected as a default. In a typical Likert scale like above, what would be the most appropriate to select as default? 'Average', as it is in the middle or 'Very good', which might appear presumptuous?
It is perfectly acceptable for a radio group not to have a default selection if you don't want to influence the user's response (such as in a survey). Microsoft provides this advice in its design guidelines for radio buttons:
Don't have a default selection if...The goal is to collect unbiased data. Default values would bias data collection.
Classic testing theory suggests you should use an even number of options as people tend to plump for the middle one. Even numbers force a more positive/negative decision.
Select a single radio button by default in most cases. Reasons to deviate or not: expedite tasks, the power of suggestion, user expectations, safety nets.