Expect to A/lake Tradeoffs

Because to some extent your participant characteristics are a projection of who you and the team are hoping the participants should be, you may find that the pool of respondents you have to select from meet some of

the requirements you want, but not all. This is when it is useful to have interviewed participants conversationally rather than by going through the multiple choice questionnaire by rote. The conversational screening allows you to ask follow-up questions that could help you decide whether a respondent is close enough to the visualized profile to give you valid data. If you or your agency use the straight questionnaire and are finding that it is difficult to schedule enough suitable participants, you and your agency should

review where the respondents are not meeting the requirements and adjust accordingly. The agency may have learned something useful that will help you eventually secure an adequate number of participants and so could go back to already interviewed respondents to ask follow-up questions. These last minute trade offs are not uncommon, and as long as you document them and account for any biases they may have introduced, it is fine to make them.