Refining conditional probative value.

• Author: Friedman, Richard D.
• Position: Response to article by Dale A. Nance in this issue, p. 419

The subject of conditional relevance, or what I think is better called "conditional probative value," must seem hopelessly arid to many. It continues to engage the attention of evidence scholars, however, because it forms part of the conceptual underpinnings of many parts of evidentiary law. Dale Nance, one of the most astute evidence scholars of our time, has previously written at length on the subject(1) and has done so now more briefly in response to an article of mine. I offer an even briefer continuation of the discussion.

Professor Nance and I have approached the topic in very different ways. My article attempts to show that, as Professor Peter Tillers put it in a very generous response, reports of the death of the concept of conditional relevance have both been exaggerated and misleading.(2) Although the concept as classically expressed in evidentiary rules is subject to some important objections, it "should not be discarded but rather refreshed."(3) I therefore tried to develop and explore these concepts in my article and show the usefulness in several contexts of the notion that an item of evidence, while having relatively low probative value when offered, might have higher probative value under some other sets of evidentiary conditions. Professor Nance's goal in his earlier contribution on the subject was, as I understood it, substantially different. He found the criticisms of the conditional relevance doctrine sufficiently persuasive that the, concept "now seems unable to bear the weight as an explanatory device that it had confidently assumed," but he believed it had "residual force" that could best be explained as an "instantiat[ion]" of the "best evidence principle."(4)

This last statement warrants careful examination. Nance has made one of the great contributions to recent evidentiary scholarship by showing the organizing force of the "best evidence" principle. The most interesting aspect of that principle, to my mind, is what Nance calls the "expansionary" aspect. Application of this aspect means that, even if a given item of evidence is more helpful than harmful to the truth-determining process, exclusion may nevertheless be warranted in hopes that it win induce the proponent to produce even better evidence. But in Nance's terms, there is also a "contractionary" aspect of the best evidence principle, which corresponds roughly to Federal Rule of Evidence 403 and provides essentially that evidence should be excluded if, on balance, it is harmful to the truth-determining process because countervailing considerations outweigh any probative value it may have.(5) There is considerable value in putting these two aspects under one head - the latter asking in essence, "Is it more bad than good?" and the former, "Even if it is more good than bad, should it be excluded in hopes of getting better?" - together expressing the search for the optimal package of evidence.

In this light, however, I believe that saying that the justifiable applications of the conditional relevance concept are instantiations of the best evidence principle tells us little that we did not know before. As it has been classically understood, the idea of conditional relevance is that absent predicate evidence, the proffered evidence, is irrelevant or put more loosely and accurately that it has too little probative value to warrant admissibility - which is much the same thing as saying that absent predicate evidence, the contractionary aspect of the best evidence principle demands exclusion of the proffered evidence.

The more intriguing aspect of Nance's approach lies in its application of the expansionary aspect. In this context, that aspect means that although the proffered evidence has sufficient probative value to warrant admissibility, this evidence should nevertheless be excluded absent the offer of predicate evidence, in light of which it would have significantly greater probative value.(6) I have used the term relative conditional probative value to express the idea that though the proffered evidence has significant probative value under one set of evidentiary conditions, it potentially - given the satisfaction of another set of evidentiary conditions - would have substantially more value.(7) I believe exclusion on this basis is clearly warranted in some circumstances - but in my own article, I have suggested that these circumstances are rather narrowly limited.(8) For the most part, if the proffered evidence is more probative than prejudicial, the court should not exclude it in hopes of inducing the production of predicate evidence, given that neither the proponent nor the opponent has decided to produce the predicate evidence. It seems to me, and this may be wishful thinking, that Nance's response to my article suggests some shift of emphasis in this direction.(9)

In my own article, I certainly gave more emphasis to the traditional realm of the doctrine, to applications of what I called near-absolute conditional probative value.(10) Professor Nance, with his usual perception, has spotted an unfortunate lack of precision in my statement of this concept. What I had in mind was the situation in which the court might conclude, in effect, "On the current state of the evidence, the proffered evidence does not have enough value to warrant admissibility, but, under another state of the evidence, it would." In other words, exclusion is warranted on the present state of the evidence, without need to rely on the possibility that...