Videos of talks (include multimedia demonstrations)


Fraser, H. (to appear) ‘Enhancing’ forensic audio: False beliefs and their effect on criminal trials. Australian Journal of Forensic Science

Indistinct covert recordings admitted as evidence in criminal trials are routinely ‘enhanced’ to assist a jury in making out their contents. But just what is ‘enhancing’, and how effective is it? This paper uses two short experiments to demonstrate that a subjective impression that ‘enhancing’ has made the audio ‘clearer’ does not necessarily indicate there has been an objective improvement in intelligibility. It then outlines, in a non-technical manner, the capabilities and limitations of various ‘enhancing’ techniques, and discusses implications in relation to current legal practices around the admission and use of ‘enhanced’ audio in Australian criminal trials. Finally it recommends that ‘enhanced’ versions of forensic recordings should only be admitted on the basis of objective evidence that they have genuinely improved the intelligibility of the specific audio being used, noting that such evidence is very easy to obtain and provide.

Fraser, H. 2018. ‘Assisting’ listeners to hear words that aren’t there: Dangers in using police transcripts of indistinct covert recordings. Australian Journal of Forensic Sciences, 50(2), 129–139.

Results are reported of a new experiment using an indistinct covert recording from a real murder trial, along with the police transcript admitted to ‘assist’ the court to hear its contents. Previous research using the same material has shown that the police transcript is inaccurate, yet nevertheless highly influential on the perception of listeners ‘primed’ by seeing words it suggests. The current experiment examines the effects of priming participants with a made-up phrase that vaguely fits the acoustics of one section of the recording. Results indicate that a very high proportion of listeners are easily ‘assisted’ to ‘hear’ the made-up phrase. Discussion argues that audio of this quality should only be used as evidence if accompanied by a reliable independent transcript.

Fraser, H. 2018. Real forensic experts should pay more attention to the dangers posed by “ad hoc experts” (Guest Editorial). Australian Journal of Forensic Sciences, 50(2), 125–128.

Recent years have seen a great deal of attention given to the reliability of expert evidence admit-ted in criminal trials. However, almost no attention has been given to the reliability of evidence provided by so-called ‘ad hoc experts’. Indeed, many forensic scientists seem unaware that such a category of witness even exists, much less of the substantial threats they pose to the fairness of our criminal justice system.

Fraser, H. 2017. How interpretation of indistinct covert recordings can lead to wrongful conviction: A case study and recommendations for reform. In R. Levy, et al (Eds.), New directions for law in Australia: Essays in contemporary law reform (pp. 191–200). Canberra: ANU Press.

Covert recording (‘bugging’) is now authorised in almost every major police investigation. Unfortunately, because the need for secrecy compromises control over recording conditions, the audio is often indistinct. Legal practice regarding the use of indistinct covert recordings in trials has evolved haphazardly over the past 30 years, with no consultation of phonetic science. This has resulted in a number of anomalies, notably the fact that detectives are allowed (as ‘ad hoc experts’) to present their own transcripts of indistinct audio to ‘assist’ the jury in interpreting the audio evidence. This chapter highlights problems with this practice via a case study of a murder conviction obtained on the basis of a demonstrably inaccurate police transcript, then suggests directions for reform.

Fraser, H. 2015. Transcription of indistinct covert recordings used as evidence in criminal trials. In H. Selby & I. Freckelton (Eds.), Expert Evidence. Thomson Reuters.

Advances in technology are making it ever easier to collect covert recordings (conversations captured on tape, or its digital equivalent, without the knowledge of the speakers). Legally obtained covert recordings potentially provide powerful evidence in criminal trials, seemingly allowing the jury to listen directly as the recorded speakers make admissions or give information they would not have been willing to give openly.

Over recent decades, the law has developed processes and practices for handling poor quality covert recordings. However, this development has involved little engagement with the science of forensic transcription and some of the practices have less than ideal results, as detailed below. There may be a case for general reform in this area, but in the meantime there is certainly a need for more critical evaluation of poor quality forensic audio used as evidence in individual cases – ideally by the side presenting them but especially by the opposing side.

This chapter aims to provide some background about the science of forensic transcription that may be useful in this regard. It starts by defining the scope of forensic transcription, then provides a brief overview of current legal practice in Australia, followed by a discussion of transcription from the perspective of the scientific disciplines of linguistics and phonetics. This allows development of a simple six-factor framework within which problems in the interpretation of poor quality covert recordings can be understood, and some directions in which solutions to those problems can be sought.

Sign up here for occasional news about Forensic Transcription (no spam!)