Guidelines for Witness Interviews During an Incident Investigation - Safetip #157

Safety Tip and Best Practice
January 30, 2019

In this week’s Safetip, we share guidelines that you can follow for the interview of witnesses during an incident investigation.

Witness Interviews Are Key to an Incident Investigation

There are many steps to an incident investigation, including:

  • Securing the scene of the incident to preserve evidence
  • Designating the incident investigation team and lead investigator
  • Collecting different types of evidence and data
  • Interviewing witnesses
  • Analyzing the evidence, the data, and witness interviews
  • Identifying root causes
  • Preparing the incident investigation report
  • Launching action plans to address root causes of incidents

Ideally you should set and follow rules or guidelines for most of the steps to ensure a successful incident investigation.

Interviewing Witnesses Can be a Difficult Task

Interviewing witnesses can be complex, and it can be one of the most difficult tasks for an investigator. Depending on the nature of an accident, witnesses can be under great emotional stress. Memory can fade or can even be flawed. Also, humans are prone to irrationalities and cognitive biases. For all these reasons, guidelines are needed to make sure that witness interviews produce valuable and accurate information.

Here are guidelines that you can adopt in your own organization based on a webpage on incident investigation from the Canadian Centre for Occupational Health and Safety and other sources:

  • Interview the witness as soon as possible after the incident.
  • Interview the witness alone, not in a group.
  • Explain and highlight the reason for the investigation (to determine what happened and why).
  • Make sure that the witness is aware that the purpose of the investigation is not to assign blame.
  • Ask if it’s OK to record the interview.
  • Make the witness feel comfortable.
  • Don’t behave in a way that may intimidate the witness.
  • Pay attention to the tone of your voice.
  • Don’t display your emotions.
  • As much as possible, ask open-ended questions that cannot be answered simply by “yes” or “no”.
  • If possible, ask the witness to re-enact the sequence of events that led to the incident.
  • Avoid questions that prompt or encourage the desired answers.
  • Don’t interrupt the witness.
  • Remember to let the witness talk and to listen to them.
  • Confirm that you have the correct statements.
  • Make also note of the witness’s feelings and emotions, not just their words.
  • Close on a positive note.

Based on your own unique circumstances, you can also complement the guidelines with other elements.

Each week we publish a Safetip where we share a safety tip or best practice that contributes to safety excellence. Visit Enablon Insights again next Wednesday for a new Safetip!

View the recording of our webinar with TapRooT® to learn how you can enable a human factors-based incident investigation lifecycle, and how the integration of Enablon and TapRooT® facilitates the tasks of incident investigators:



Jean-Grégoire Manoukian

Content Thought Leader