Skip to content
2 minute read

How to assess credibility

Has this ever happened to you?... You’re in the middle of an investigation and two of your witnesses tell you different stories about what happened. How do you decide whether either of them is credible?  

In any workplace investigation, what you need to learn are the facts. You do this by gathering evidence—collecting information that supports a significant aspect of an investigation and aids in either confirming or refuting an allegation.

This is important because, at the end of the process, the quality of the evidence determines whether others will accept your findings. 

The trouble is, as an investigator, you will encounter conflicting information from witnesses. There may be several reasons for the conflict, but it is still a conflict, and the challenge is determining which version of the facts is more reliable as a piece of evidence.

Many investigators resolve the conflict by asking themselves which of these two witnesses they believe is telling them the truth. This is a mistake. The investigator's views, perspectives, opinions, and institutional knowledge are not evidence. Remember, the investigator is a fact-finder.

Instead, the weight you as the investigator should give a piece of evidence depends on these three factors:  

  1. the basis of the witness's knowledge
  2. whether the evidence is direct or circumstantial
  3. the credibility of the evidence

Since our focus in this blog is on credibility, let’s take a look at how to unpack that. 

[Editorial note: The other two are very important, too! Check out Meric's website at the link below for resources on other investigations topics.]

So, how do you assess credibility? 

Before the interview even really begins, you need to establish rapport and set the tone. Start with some neutral questions to help break the ice and get your witness comfortable in the moment. This tactic will also help calm the witness’s nerves, so you have a baseline of his or her regular verbal and non-verbal communication patterns to help assess cooperation, honesty, and credibility.

Now we’re ready to assess credibility! But you’re not going to do this part during the interview. Stay focused on asking the questions to assess facts and record the answers. Then, when you go back to review the information you’ve collected, also consider these factors:

  1. Was the witness present and aware during the incident?
  2. How well developed are the witness’s powers of observation?
  3. Is the witness’s story logical? Does it make sense? 
  4. What was the witness’s demeanor during the interview?
  5. Did the witness make contradictory statements?
  6. Does the witness have a reason to lie about any aspect of the incident?
  7. Does the witness have any known or suspected bias?
  8. Does the witness stand to benefit in some way from a certain outcome?
  9. What are the witness’s relationships to other witnesses and the subject of the investigation?

Remember: your goal, after you gather the facts, is to assess credibility to determine if the witness’s evidence is reliable. Information that appears relevant is useless unless it is also credible.

Do not assess credibility by simply deciding which witness you believe. Use these questions to help you stay objective and make a solid assessment. Your investigations will be better for it! 

Did you miss Broadcat’s investigations Q&A webinar with Meric? 

Listen here and download tips for a quality investigation, as well as how to write and finalize your investigation report. And follow us on LinkedIn to hear Meric respond to some questions we didn't get to during the webinar!


Meric has conducted over 800 workplace investigations globally, and has trained thousands of HR and compliance professionals to conduct investigations. He is a Certified Fraud Examiner, a Professional Certified Investigator, a Certified Financial Crime Specialist, a Certified Information Privacy Professional, has the Corporate Compliance and Ethics Professional – Fellow designation, and is an adjunct professor at Fordham University School of Law. 

Meric is the author of four books on investigations. You can reach him at or

Don't miss out!

Get compliance tips and resources delivered straight to your inbox.