Why was this review needed? The answer is that there is evidence to suggest that jurors can face considerable challenges in recalling both the evidence and the legal directions in a criminal trial and that they can struggle to understand legal directions. This is perhaps not surprising. The evidence in a jury trial will often be given over the course of several days or weeks. Legal directions can be complicated, especially where there are multiple charges or several accused, and it is worth bearing in mind that that jurors enter the courtroom with (most likely) no existing legal knowledge and are drawn from all walks of life. The deliberation process – whereby individual jurors pool their knowledge – assists to some degree in terms of helping the jury to remember the evidence but it is less effective at improving the comprehension of legal tests.

What did the review find? Eight methods of improving memory and/or comprehension on which at least some empirical evidence exists were identified: trial transcripts, juror note-taking, audio-visual and digital presentation methods, juror questions, pre-instruction, plain language directions, written directions and structured decision aids (also known as routes to verdict). Aside from juror note-taking, none of these methods are routinely used in Scotland at the moment.

Which method is most effective? The answer is that different methods target different issues – some improve memory, some improve understanding and application of legal tests – and there is evidence to suggest that they may be best used in combination, rather than as alternatives.

In terms of enhancing juror memory for the evidence, the most effective methods appear to be juror note-taking and pre-instruction. Juror note-taking refers to the practice of encouraging jurors to take notes during the trial and providing them with materials to do so and there is evidence to suggest that this assists jurors to remember the evidence they have heard, especially if they are given trial-ordered notebooks (structured notebooks that help jurors to organise their notes). The evidence also suggests that juror note-taking is at least as effective – if not more so – than providing jurors with a full transcript of trial evidence. Given that a trial might last days or weeks, a full transcript is likely to be difficult for jurors to navigate, not to mention time consuming and expensive to produce. Perhaps more surprisingly, there is evidence that pre-instruction – the practice of directing jurors on the substantive legal issues in the case before evidence is led – can also improve memory of the evidence. The reason for this may be that it assists jurors in identifying relevant evidence as it is led and provides a framework for organising this. Despite concerns that pre-instruction might cause jurors to reach their verdict decisions prematurely, there is no indication from the relevant studies that this is the case.

There is also evidence that pre-instruction improves juror memory for legal directions – most likely for the straightforward reason that jurors hear the main points of the directions twice (pre-instruction takes place in addition to post-instruction, not as a substitute for it). There is, however, a far more obvious method of improving recall of judicial directions, which is to provide directions to jurors in writing and, unsurprisingly, empirical research demonstrates that jurors who are provided with written directions are better able to remember and re-state those directions.

In terms of improving juror comprehension of legal directions, the most effective methods appear to be plain language directions and structured decision aids (routes to verdict). Plain language directions are legal directions that have been simplified as much as possible in terms of their language, grammar and syntax (while still retaining their essential legal meaning). There is a vast body of evidence to suggest that simplifying jury directions can improve juror comprehension of legal concepts, although the majority of this stems from studies undertaken in the US, where jury directions do tend to be longer and more complex than those in Scotland.

A structured decision aid (a ‘route to verdict’) is a series of primarily factual questions – which might be presented as a series of written questions or in diagrammatic or flowchart form – that gradually lead jurors to a legally justified verdict. Routes to verdict are a relatively recent innovation and the evidence base is still developing. The evidence that does exist (particularly from the better designed studies) suggests that, compared to simply giving jurors a written copy of the trial judge’s directions, routes to verdict are more effective at improving ‘applied’ comprehension – that is jurors’ ability to correctly apply legal tests to the evidence.

The full report can be found here and a summary of research findings can be found here.