Competency of Witnesses

With all the complicated content tested within Evidence questions, the question as to what makes a witness competent to testify may seem simple, but the issue shows up and it's important to know how to address it. It might first be noted that witnesses are presumed competent until the contrary is established. But to determine whether the contrary has been established, the rules for competency are important.

There are two basic requirements here: witnesses must have personal knowledge of the matter that is the subject of the testimony, and the witness must declare he/she will testify truthfully.

If the witness requires an interpreter, the interpreter must be qualified and must take an oath to make a true translation.

A few situations occur often enough that it's helpful to note them. The competency of an infant will depend only upon the infant's capacity to testify and the trial judge can make this determination. A person who has been adjudicated insane may testify provided the person understands the obligation to speak truthfully and has the capacity to testify accurately. A presiding judge may not testify as a witness nor may jurors testify before the jury in which they are sitting.

The Dead Man Act never seems to die. These acts generally provide that a party who stands to gain or lose by a judgment is incompetent to testify to a personal transaction or communication with a deceased person when such testimony is offered against the representative or successors in interest of the deceased. There is advice often given that the Dead Man Act is always a wrong answer on the MBE. This isn't far from the truth, but it should be noted that although there is no Dead Man Act in the Federal Rules, a state Dead Man Act can still apply where state law, under the Erie Doctrine, provides the rule of decision (for example, when a case is in federal court based only on diversity of jurisdiction).