South Carolina Supreme Court Justice John Few teaches and speaks about the Rules of Evidence quite often. Out of all of his teachings though, one of the most important comes down to a simple question:

One of the most important questions a trial lawyer or judge can ask in thinking through a particular evidence problem is, ‘Why is the evidence being offered?’ There are two primary reasons for this. First, evidence struggles arise in the context of real problems faced by real people. So, to properly understand any evidence problem, lawyers and judges must understand the practical context in which the underlying problem arose. Focusing on the reason the party has for offering a particular piece of evidence draws us farther into this practical context. … Second, and most importantly, the purpose for which the evidence is offered relates directly to its admissibility. … But keep this very important principle in mind! The person offering the evidence does not get to choose what her purpose is. She gets to argue what her purpose is, but the other side gets to argue the point as well.[1]

This approach clarifies and narrows the potential evidentiary issues that are presented to a trial judge. By forcing the proponent of the evidence to explain the purpose of the evidence, the judge can figure out what rule or rules they should consider. Now, just because the proponent says what their purpose is, does not mean that is the true purpose, or the purpose that the jury will take. But it is a starting point.

[1] Few, John Cannon. “‘Why?" Is a Critical Question in Evidence!” Art of Evidence, 12 Sept. 2018, artofevidence.com/2018/09/10/why-is-a-critical-question-in-evidence/.