MBE Rules · Evidence
Witness Competency
FRE 601-603
The rule
Every witness is presumed competent; the proponent need only show personal knowledge and an oath or affirmation, and in diversity cases state competency law governs claims decided under state law.
In plain English
Witness competency means that anyone can generally testify in court unless proven otherwise. To be considered competent, a witness must have personal knowledge about the matter at hand and must take an oath or affirmation to tell the truth. In cases involving diversity jurisdiction, the law of the state where the case is being heard will determine witness competency.
Worked example
In a personal injury case, a bystander who saw the accident is called to testify. They confirm they witnessed the event and take an oath to tell the truth. Since they have personal knowledge and affirmed their commitment to honesty, the court finds them competent to testify.
Memory hook
Every witness can speak, just show they know and swear!
The trap
Exams may present scenarios where a witness seems unreliable or biased, leading students to question competency when the basic requirements are met. Students might overlook that personal knowledge and an oath are the only necessary criteria.
How examiners test it
Questions often involve scenarios where a witness's background or relationship to the case is scrutinized, testing whether students can identify the basic competency requirements despite potential biases.
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