A fascinating guest post today from Dr Tim Grant, Senior Lecturer in Forensic Linguistics at Aston University in the UK, and the Director of the Centre for Forensic Linguistics there.  His main research interests are in forensic authorship analysis and in the conversations which occur between attackers and victims in cases of serious sexual assault and rape. He has publications in both of these areas in both psychology and linguistics journals. His consultancy has largely involved the analysis of abusive and threatening communications in many different contexts including investigations into sexual assaults, murder and terrorist offences. It has also included cases of copyright infringement and academic plagiarism.

* * *

A Google alert just threw up this fascinating blog post from “Suesspiciousminds” (good name!).  The post contains a discussion of a recent Court of Protection case at Birmingham County Court.  Court of Protection cases involve vulnerable individuals (adults or children) and so routinely use witnesses’ initials rather than full names – I hadn’t realised before that this also extends to expert witnesses.  This case however uses forensic linguistic evidence of Professor C,  Emeritus Professor of forensic linguistics from Aston University and Professor PJ of Duquesne University, Pittsburgh, USA.  I’m not sure if it would be Contempt of Court for me to name these individuals but forensic linguistics is a small world and those in the know will be in the know and for everyone else there’s Google.

The case concerns the authorship of a disputed will and Suesspiciousminds’ write up is worth the full read.  The judgment can be consulted here and you should read that too.

Three points of the case and Suesspiciousminds’ write up particularly leapt out at me.

First, Professor C’s conclusion, as cited by the judge, was cautious.  Prof C is one of the world’s most experienced expert witnesses in the field of forensic linguistics and his opinions have been upheld at the Court of Appeal as being appropriately cautious.  This leaves the judge saying (at para 63)

“he is much more cautious than Professor PJ and Professor PJ’s evidence, is therefore, the more important.”

This judicial opinion in and of itself interests me.  I’ve heard lawyers in the past describe someone as a “good” witness meaning that that witness had a high degree of certainty in their evidence.  As a practicing forensic linguist I wouldn’t view a higher level of certainty as making evidence “more important” or “good” and I’m happy to assume the intelligence and competence of the judge so this leaves me feeling that the legal view of evidence as being “good” or “important” must have a some slightly slippery technical legal meaning that I’m not grasping.

If you’ve got any thoughts on this do get in touch…

Second, there is a discussion of Prof PJ’s method.  Suesspiciousminds’ discussion of this evidence raises issues that I’ve argued for years.  Forensic authorship analysis work, I feel, should not depend on heavily computational, black box approaches, (no matter how sophisticated nor how low the published error rates in research articles).  For me, forensic evidence requires appropriate caution and explanation of results.  The computational systems, however good, cannot answer the range of Suesspiciousminds’ questions, but more importantly (and as a matter of principle) neither can Prof PJ. My feeling is that this kind of evidence cannot be properly interrogated and therefore is not strong evidence.

Once again I’d be interested in your views?

Finally, although by no means the final point of interest in the post or the judgment, we come to para 92.  The judge is concerned about

“a slightly worrying aspect of Professor PJ’s evidence which to an extent affects its standing; that is, the manner in which he had become involved. In saying this I make no criticism of the solicitor or counsel for PS. The letter of instructions was perfectly proper. But in evidence Professor PJ agreed he had accepted instructions as a favour to Professor C, whose conclusions, as I have set out, are somewhat uncertain.”

This concern leads the judge to view Prof PJ’s evidence in and of itself with some caution.  I’m guessing that from Prof C’s perspective, he probably thought that involving an alternative practitioner, with very different methods to his own, might provide valuable additional information to the Court.  Such is the collegiate ethos of the Academy at its best and I might have done the same.  The professionally jaundiced eye of the Court views such cooperation differently.

The International Association of Forensic Linguists (IAFL) is about to publish its draft code of conduct and I don’t think it touches on such potential ‘conflicts’ of one expert identifying and involving a second expert in a case…

* * *

You might also like to read this post: What exactly is forensic linguistics? which includes a video with Dr Grant (with a very insightful section near the end on police interview interpreting). Do check out his Scoop.it topic here. Another video on Dr Grant’s Centre for Forensic Linguistics and on improving the delivery of justice can be found here.