Guest Blog: The Conversation Analyst as an Expert Witness in the Courtroom

Some court cases rely on the interpretation of verbal exchanges – recorded conversations, interviews, police interrogations. The expert may be asked to say whether something is evidence of a bribe, a threat, a confession, and so on. Gary C. David PhD CCS is one of the very few conversation analysts who have been called on to help the court. His report makes for fascinating reading.

Gary C David, Bentley University

When is an interrogation and interview, or an interview an interrogation? How much does it matter how such encounters are characterized versus what they look like? How can we tell the difference between the two? These are questions that I had to address as I was asked to examine a police encounter with a person suspected of murder. My expert opinion could make a difference in whether evidence is admitted or excluded, and whether the suspect goes to trial or goes free.

For the past approximately seven years, I have been working on legal cases in which police interviews and interrogations have been called into question. I originally started this work with retired Detective Jim Trainum, a nationally recognized expert on false confessions. I got to know of Jim’s work through hearing him on an episode of This American Life, where he was discussing his role in unknowingly producing a false confession. After reviewing the video recording of the police interrogation, he was able to identify how he and his partner generated a false confession. As he retold this story, I immediately saw the potential for conversation analysis to contribute to this work. After contacting him and introducing myself, he agreed, and we have been working together ever since.

Coercion and contamination

Typically, I work on cases in which the police/suspect encounter is called into question, focusing on whether coercion and/or contamination produced a false confession. Coercion would involve law enforcement creating duress for the purposes of getting a confession, such as promising (or even strongly implying) a reduced sentence in exchange for a confession. Contamination involves law enforcement providing details of the crime to such an extent that it can’t be known whether the suspect was really there, or just repeating what they were told.

When working on these cases, I position CA under the category of forensic linguistics, which broadly includes approaches focusing on the nature and impact of oral and written communication/language occurring in legal contexts. Conversation analysis has been identified as part of that field, especially for the purposes of research and scholarship. However, I don’t believe CA has been introduced as a scientific area of analysis in criminal proceedings. Until now.

A typical US police interrogation scene (Source: Youtube)

An example case: interview, or interrogation?

For one particular case, I was asked by defense counsel to evaluate a police encounter with a suspect to determine whether it was a non-custodial interview or a custodial interrogation. This determination is important because it determines whether or not the suspect’s Miranda rights need be given. I was asked to use my training as a conversation analyst, my participation in police interrogation training programs, and my previous work on other cases to render an expert judgment on whether the encounter was an interview, interrogation, or both. To do so, I reviewed the following materials:

  • The police encounter with the suspect, both audio recording and official transcript
  • Transcripts from pre-trial hearings
    • Police reports from the investigation

In the United States, the primary method of interrogation is known as an accusatorial approach, meaning that the goal of the encounter is to get the suspect to confess to the crime. This can be compared to the information-seeking interview where the investigators are looking for information regarding the crime. Each is identifiable by the conversation structures present, as well as the tactics used. Thus, determination of interrogation or interview is not a matter of opinion, but a matter of examining the structures and practices

Working with the court

In my role as expert, I had the opportunity to be part of a pre-trial motion hearing where I shared my analysis with the judge, the prosecutor, and the defense counsel (with whom I was working). Part of that process included trying to explain what conversation analysis is and how it was applicable to this case. In doing so, I was able to establish that forensic linguistics and conversation analysis are scientific methods that can be used for the examination of police encounters with suspects. As a result, the court deemed that CA is an appropriate tool for rendering judgments on the nature and structure of these interactions.

A number of CA’s features were important as part of testifying.

First, that we rely on analysis and description rather than interpretation and assessment of mental states which can raise objections in courts in terms of admissibility.

Second, the ability to go “back to the data” in the form of the transcript as forms of evidence to support our analysis. It is not my opinion that this is happening; I can point out where and how it is happening in the transcript and recordings.

Third, focus on audio (or video) recordings to explore parts of the encounters that are not rendered on the official transcript. This focus on listening also is important in terms of checking the accuracy of the official transcript. Fourth, the corpus of conversation analytic work and concepts that have come before which can be used in the examination of police/suspect encounters.

My judgement to the court

I was able to come to a firm conclusion for the court. My assessment was that the encounter was, in fact, an interrogation: it had the conversational structures and interrogation tactics associated with an interrogation. This wasn’t my expert opinion, but rather my expert analysis.

While I don’t currently know the outcome of my testimony, I do know that the three hours that I spent testifying allowed me to highlight the importance of conversation analysis in the examination of police/suspect encounters. Defense counsel admitted that he was skeptical of what I could contribute going in, but then realized the importance of CA in the examination of such encounters. As more CA work is done as expert testimony, we can expect more people to see the value that CA can contribute to legal cases and courtroom proceedings.

Gary David is a Professor of Sociology and Experience Design at Bentley University (Waltham, MA). You can read more about his work and thoughts at  You also can learn more about his professional and consulting work at