Pennsylvania Rule of Evidence 401 directly deals with relevance and potential objections. There are a host of cases, like Commonwealth v. Boczkowski of 2004, that establish that evidence is relevant if it logically tends to establish a material fact in the case or tends to make a fact at issue more or less probable or supports a reasonable inference or presumption regarding a material fact.
It is important to note -- evidence relating to credibility is still relevant. But, these seemingly simple rule gets examined a lot further and is important for all Bucks County Criminal Defense Lawyers.
Commonwealth v. McNeely from 1987 created a really strong prong test for the issue of relevance. The court breaks down relevance into two parts:
- Materiality - what is the relation between the propositions for which the evidence is offered and the issue in the case?
- Probative value - the tendency (does it make it more likely or less likely?) of the evidence to establish the proposition that it is offered to prove?
Remember with materiality-- if something is offered to help prove a point which is not a matter in the issue, you have offered evidence which is immaterial.
There is another aspect to probative value and one you've probably heard on a crime show before -- relevant evidence may be excluded if its probative value is outweighed by the danger of unfair prejudice, confusion of the issues, misleading of the jury, wast of time or needless presentation of cumulative evidence (see Pa. R.E. 403 and the case of Henery v. Shadle of 1995). One key word in this description is "unfair prejudice". Of course a prosecutor will present some evidence that will prejudice you (after all, they are seeking your conviction). But, is the prejudice unfair?
Typically, unfair prejudice in my experience in the Bucks County courts revolves around the evidence enflaming a jury. Gruesome photos of a crime scene is a standard example.