One of the first evidential rules taught to students of criminal evidence is the requirement that all evidence in a criminal trial must be relevant before it can be admitted. Relevance has been described as ‘possibly the most basic concept in the law of evidence’ and works quietly and (supposedly) uncontroversially to regulate the admission of evidence. Its importance should not be underestimated though, it applies universally to all pieces of evidence and, if established, means evidence is prima facie admissible and may be put before a jury. Given this central role of relevance in criminal proceedings, it is important that we understand what relevance is, what it means, and how decisions on evidential relevance are made in practice.
As part of a doctoral research project, I interviewed 20 criminal barristers on the topic of relevance, and some highlights of those interviews are shared with the reader here. In headline terms, barristers generally saw relevance as a relatively straightforward matter, which posed them few practical difficulties. However, subsequent questioning on the detail of relevance revealed that barristers’ approaches to relevance varied considerably, and that they understood relevance in quite different ways from one another. Far from the simple, straightforward concept it is often held out to be, my data suggests a more complex and context-specific picture, raising questions about the fair and consistent application of the ‘foundational concept’ in practice.
Before exploring interview responses, it is useful to set out some of the basics of relevance as an evidential concept.
What is evidential relevance?
At its most basic, evidence is regarded as relevant if it has a bearing on a matter requiring proof. It is generally said that a piece of evidence will be relevant if it makes a matter requiring proof more probable or less probable. Once evidential relevance is established, the evidence in question is prima facie admissible. Of course, relevance and admissibility are distinct from one another, and that which is relevant may subsequently be inadmissible by virtue of the exercise of an exclusionary rule of evidence or exclusionary discretion. Paul Roberts usefully sets out the admissibility structure in three key questions:
- Is the evidence relevant?
- Is the evidence subject to an exclusionary rule of evidence?
- If yes, is the evidence subject to an inclusionary exception to the exclusionary rule?
This structure shows where relevance is situated within the wider admissibility process, and the importance of its role therein. However, despite its fundamental function, there has been relatively little academic or practitioner discussion of relevance in the literature. Where discussions on relevance have taken place – at least in the academic arena – they have tended to focus on the high-level distinction between two ‘tests’ for relevance: ‘logical relevance’ and ‘legal relevance’.
In short, logical relevance presents evidential relevance as an ‘affair of logic and not of law’, requiring that the evidence must simply have some logical and common-sense rationale for advancing a fact in issue. Once a logical connection between the evidence and fact in issue is established, no additional threshold needs to be surpassed. Legal relevance differs in that it requires an additional assessment be made as to the probative value of the evidence. It asks the same initial question (is the evidence logically relevant to a fact in issue?), but then requires that the evidence has sufficient ‘plus value’, that is, probative value. Legal relevance can be neatly expressed as ‘logical relevance + plus value = legal relevance’.
Academic discourse has tended to focus on the high-level theoretical distinction between these two tests of relevance, but in doing so has neglected important questions of detail and practice. Even the most basic question of which of the two tests is/should be preferred in practice is invariably left unanswered. To investigate this and other questions about how relevance works in practice, I interviewed 20 criminal barristers, most of whom had experience with both prosecution and defence work, and who had between 6 – 46 years post qualifying experience. Some important headlines from the data are shared here; with a more complete account to follow in a full-length journal article.
Views from the Bar
I asked all interviewees to offer their views on how evidential relevance works in practice, and whether they felt relevance was dealt with consistently in the criminal courts. Most barristers expressed the view that relevance was dealt with consistently by fellow barristers in the criminal courts, and projected a view of relevance as a well-settled, straightforward evidential requirement:
B17: It is usually a straightforward exercise, and dare I say … quite … obvious whether something is relevant or not.
B12: It’s just if something’s not relevant, that is normally screaming out … whether or not it is relevant is rarely something that is balanced on a knife edge.
Other barristers shared the view that relevance was an uncontroversial matter, but acknowledged how the same approach towards relevance might lead to different results in different cases. Even where this was acknowledged, however, the core contention remained: there were no substantial differences in the tests that barristers attached to relevance, it is merely that the application of that test may sometimes lead to differing outcomes. Consider the following response:
B2: I don’t think there is an inconsistency as to the law that is being applied. I do think, undoubtedly, there are inconsistencies of approach between judges and between lawyers, as to whether something genuinely is or isn’t relevant. I suppose in theory, if someone gets it wrong, that’s what is corrected by the Court of Appeal who can then say well actually that was relevant to this issue.
However, despite the high-level view of settled law and consistency, subsequent questioning of barristers revealed some important differences in the ways in which they understood evidential relevance.
This was most apparent when barristers were asked to give their view on the two prevailing tests for relevance outlined above, logical relevance and legal relevance. I gave barristers a brief explanation of these two tests, and asked if they recognised or favoured either of the tests in practice. The responses showed significant differences in understanding of relevance tests and there was no consensus among interviewees as to which was the appropriate test for relevance. Some favoured legal relevance due to its capacity to assess the probative value of the evidence:
B3: I think the [legal relevance] test because you have the added-on issue of probity and I think when you are taught the law, the law of evidence, you kind of remember Section 78 [of the Police and Criminal Evidence Act 1984] … that’s one of those things that stick in your mind … it is quite a nice test, it’s one most people can get. So I suppose you would look logically first of all, then you do add the second test.
B1: I think there’s a real danger in the second one [legal relevance] … I’m thinking more of an investigative aspect … now the difficulty is if you apply that probative test, that material will be in effect lost, because it won’t even appear on the disclosure schedule and that creates a problem.
B12: The difficulty with the second one [legal relevance] is that I think that it’s applying the test at the wrong time. If something is relevant, then it’s admissible. However, if its probative value is outweighed by its prejudicial impact then it should be excluded, pursuant to Section 78 of the Police and Criminal Evidence Act 1984. I think it’s to conflate the two. The second … definition you gave relevance [legal relevance] has to be, in my view, given a very broad and wide scope, because we have the other safety nets further along in order to exclude relevant evidence.
Some barristers did not favour either test and instead thought that the appropriate test for relevance was a mix between logical relevance and legal relevance:
B2: I think it probably is just a mish mash in practice … I think most people in daily practice just approach it without really thinking whether what they are using to decide that question was strictly speaking a question of logic or by relevance to a legal test … they’re only going to start focusing on specific legal definitions of relevance … if they’re obliged to assess a statutory gateway.
These excerpts indicate the different and distinct ways that barristers can understand the test/s for relevance. That there was no consensus among the sample of 20 barristers is an important finding of itself. Of course, this sample is not generalisable across the legal profession, but it is indicative of the difficulties associated with the ‘deceptively simple’ notion of relevance. None of this is intended as a critique of the barristers interviewed or the different views posed; instead, it serves as a stark reminder of the importance of understanding discretionary tests – such as relevance – and how they work in practice.
Beyond headline differences of this kind, my data also reveals a host of other factors (outside of the standard tests) that barristers take into account when assessing the relevance of evidence, from trial tactics to outside perceptions. Again, such considerations are not ‘right’ or ‘wrong’, but to the extent that they materially impact the admission of evidence, and to the extent that they are applied inconsistently between professionals, they require examination. This is taken up more fully in my journal article, and particularly within my thesis.
Conclusion
Relevance undoubtedly plays a central role in criminal proceedings, and it is essential that we understand its use in the criminal courts. The snapshot of findings shared here indicate that relevance is far more complex than is typically appreciated, and open to different interpretations and understandings. Interviews with barristers showed no consensus as to which test or approach to relevance was correct; leaving a picture of relevance as a multi-faceted and deceptively difficult evidential matter. The question remains whether this a satisfactory position for a fundamental evidential rule responsible for regulating the admission of evidence. Law generally strives for clarity and consistency; the data shared here gives reason to challenge whether relevance in its current form is serving these important ends. This is important for our understanding of relevance as a foundational evidential test; as well as for those using the concept of relevance within other exclusionary rules, as we see most recently with the Law Commission’s proposal for an ‘enhanced relevance’ test to replace current sexual history evidence exclusions.