The doorknob phenomenon or doorknob statement is something most doctors are familiar with. A patient spends 20-30 minutes with the doctor and waits until the very last moment of the appointment — often while they’re about to turn the doorknob to exit the examination room — to share something that, not uncommonly, provides crucial information about their condition.
For example, a patient spends most of the appointment talking about minor things and only reveals their most disruptive symptom just before leaving. The doorknob phenomenon is also known as an “exit line” to highlight its dramatic effect.
This phenomenon is also very common in user interviews (and probably, most kinds of interviews). Once you wrap up the interview and stop recording, interviewees suddenly start talking about one of the biggest pain points they’re having.
What can we do about it?
We can learn a lot from medicine. This is a big problem for clinicians and there’s some published research on the matter. Apparently, the best remedy is to simply ask patients: “Anything else?” at some point during their appointment. It doesn’t matter when this happens but this usually gives them a chance to open up and prevent the doorknob phenomenon. You can use a similar approach in user interviews and ask participants “Is there anything else you would like to share?” or “Did we miss anything? Is there anything you’d like to tell us?”.
I always follow Steve Portigal’s advice on this and I never stop recording a session until the very end of it. Wait until the participant leaves and then press stop!
Another way to prevent the doorknob phenomenon is by embracing awkward silences. Don't rush to talk as soon as the participant stops speaking. Intentional silence is a valid interview moderation technique. Deliberately staying silent for longer periods than it feels comfortable might encourage interviewees to share more information with you — let the users be the ones who fill in the awkward silences!