Getting better information by not pushing for answers.
Allowing uncertainty – guideline
If a witness is unable to be specific then the officer or staff should not push them to provide an answer.
Evidence drawn from three experiments using student samples indicated that allowing interviewees to provide 'don’t know' responses improved recall accuracy, particularly when there was a delay between witnessing an event and questioning. Five other laboratory-based experiments that used computer-administered questioning indicated that, when forced to give more specific answers to questions, witnesses are less accurate than when able to choose how specific their answers are.
Avoid forced answers
Research shows that witnesses are less accurate when forced to give more specific answers to questions than when they are able to choose how specific they are. Forcing a witness to give a response should therefore be avoided. For example, when estimating the time of an incident, witnesses should be allowed to be as precise as they like. If a witness says an event was between two and three hours ago, they should not be pushed for a precise time as they may give false information.
If there is a need to push for a more specific answer for operational reasons, the witness should be asked how sure they are of their answer, and the less specific answer should be recorded too. This will ensure subsequent investigations are not misdirected by inaccurate or uncertain information.
Not pushing for an answer
Hints and tips from existing guidance
Explain to the witness that, if you ask a question they do not understand, or one they do not know the answer to, they should say so – it is acceptable to say 'I don’t know' or 'I don’t understand'.
Hints and tips from the front line
One practitioner indicated that, when taking an initial account from a child, they would tell them it’s OK if they don’t remember. They felt this would help to reassure them during the initial account process.