The first questions have the purpose of making sure that the persons are in the target group.
Remember the overall question is:
Can the design use just a little less material and still fulfil the user/consumer requirement?
Present different packaging designs to the test person and ask questions about the function of the design. As an example we can still use the case about ergonomics and elderly persons. In this case a short questionnaire could be like:
1. Sex: (male/female)
2. Age: years
If the person does not fulfil the specified criteria you kindly thank them for helping you, but as the person is not in the target group you stop the interview.
4. Here is packaging proposal A (test sample). Please try to open the package. What is you evaluation of design A:
- Impossible to open
- Difficult to open
- Easy to open
- Too easy to open
5. Her is proposal B…… and C etc.
6. At last the overall question. What design proposals can you accept, and what design proposals do not work.
A short questionnaire will be sufficient and do not take long time to make the interviews and analyse data. In the end you will have documentation but only a little extra information about your product.