Which of these things is most like the others? The Reference Class Problem

The central requirement of the rule of law is equality before the law, which means that like cases ought to be treated alike.  One of the fundamental problems to valuing cases is to determine what casesare alike under what measures such that its fair to say they are worththe same amount (or fair to say that in fact they are different).

The question of whether a group of cases are sufficiently alike that they ought to be similarly valued (or have similar outcomes along some other measure, such as causation) is referred to as the “reference class problem.”  I’m just going to focus on the question of value in this post.  How do we decide what measurable criteria we are going to use to determine that some cases fall into the same categories? Should we worry that there are unmeasurable or subjective characteristics of particular cases that juries would consider but that cannot be accounted for in a statistical or qualitative social science model of valuation? 

Edward Cheng (Brooklyn) purports to solve this problem in a recent essay in the Columbia Law Review.  Click the link here for a summary of his ideas. I linked to his piece on SSRN previously (A Practical Solution to the Reference Class Problem).  Unfortunately, even if we can make some progress under Cheng’s theory, we must still balance the fit of the model to the data, and that means deciding which variables are “noise” and which are relevant, and accounting for what Donald Rumsfeld would call “unknown unknowns” – variables that we are not able to ascertain but that do end up being relevant. Cheng himself admits in the paper that it doesn’t solve the extrapolation problem, which is our main concern in mass torts.  On the other hand, I think Cheng has it right that we need to consider how rigorous social science methodology can help us solve these types of problems or at least move us a step closer to a solution that will satisfy the equality principle.  He should be commended for moving us a step forward in that direction.  I will have more on this in a forthcoming article.

ADL

(hat tip: Emily Wall, Columbia Law Review)