I agree open-ended questions in a screener are best.
But one reason some usability professionals use 'yes/no' questions is because they don't have confidence that the external recruiters can effectively assess what an acceptable open ended answer would be.
In some cases, they may find that asking a 'yes/no' question is the safer approach.
How would you handle this concern?
You asked a great open-ended question! What you need is a smarter recruiter.
There are two things you can do to make your recruiter smarter: brief her on the study, and give her the answers.
Brief your recruiter
Basically what we’re talking about is giving your recruiter enough literacy in the domain you’re in to be intelligent when screening rather than a human SurveyMonkey. You can make them work smarter for you by doing two things:
- Spend 15 minutes before the recruit starts explaining to the recruiting agency the purpose and goals of the study, the format of the sessions, what you’re hoping to find out, and who the participant is. For this last, you should be able to give the agency a one- or two-word envisionment of the participant: “The participant has recently been diagnosed with high cholesterol or diabetes or both and has to make some decisions about what to do going forward. She hasn’t done much research yet, but maybe a little.”
- Insist that the agency work with you. Tell them to call you after the first two interviews they do and walk through how it went. Questions will come up. Encourage them to call you and ask questions rather than guessing or interpreting for themselves.
With this training done, you can trust your recruiting agency a bit more. If you continue to work with the agency, over time they’ll learn more about what you want, but you’ll also have a relationship that is more collaborative.
Tell the recruiter what the answers might be
Now, to your question about Yes/No.
Using Yes/No leads to one of two things: inviting the respondent to cheat by just saying “yes!” or scaring the respondent into giving the “wrong” answer because it might be bad or embarrassing to give the “right” answer. In the screening interview, this can be scary or accusatory to the respondent: “Do you have high cholesterol?” (And saying “no” would disqualify him from the study.) Or just super easy to say “yes” because the question is too broad or ambiguous. “Do you download movies from the Web?” could be stretched to mean ‘watch videos on YouTube,’ or bit torrenting adult entertainment, but what it means is ‘Do you use a service from which you get on-demand or instant access to commercial, Hollywood movies and then watch them?’
If it’s the main qualifier for the study – Do you do X? – that can be avoided by putting out the call for participants the right way. Check the headlines on craigslist.org (usually in Jobs/ETC or in Volunteers), for example. There you’ll see pre-qualifying titles on the postings, and that’s the place to put the question, “Do you have high cholesterol?” or “Do you use a headphone with your mobile phone?” You still have to verify by asking open-ended questions.
If you find yourself wanting to ask a Yes/No question:
- Craft an open-ended question and provide what several possible right answers might be for the recruiters to use as reference (but not something they should read to respondents). Possible alternative script for the recruiter:
“Tell me about the last cholesterol test you had. What did the doctor say?”
[Recruiter: Listen for answers like this
___ He said that I’m okay but I should probably watch what I eat and get more exercise. My total cholesterol was <-200>.
___ He said that if I didn’t make a change I’d have to start taking meds/a prescription/away my cheese. My total cholesterol was <200-239>.
___ He said that I am a high risk for heart disease. I could have a heart attack. My total cholesterol was <240+>]
- Think of one key question that would call the respondent out on fibbing to get into the study. For a gaming company, we wanted people who had experience with a particular game. Anyone can look up the description of a game online and come up with plausible answers. We added in a question asking what the respondent’s favorite character was and why. Our client provided a list of possible answers: names and powers. The responses were fascinating and indicated deeper knowledge of the game than a cheater could get from the cover art or the YouTube trailer.
The short answer: You should still avoid Yes/No questions in screeners. First, think about what you’re really asking and what you want to find out by asking it. Is it really a yes/no question? Then train your recruiter a little bit beforehand, and anticipate what the answers to the open-ended questions might be.