Witness

MBE questions often hide a personal-knowledge defect inside a fact pattern that looks like a hearsay or opinion problem. The “tell” is testimony about something the witness only heard about or assumed: the answer hinges on Rule 602 — a lay witness who lacks the required personal-knowledge foundation may not testify to that matter at all, a threshold you reach before any hearsay analysis. The modern rule (Rule 601) also abolished the old categorical disqualifications: children, the mentally impaired, and convicted felons are presumptively competent; those facts go to weight and credibility, not admissibility (some older banks still list “infancy” or “insanity” as automatic bars).

The classic trap is confusing three sibling doctrines. Personal knowledge governs whether a witness may speak at all; opinion governs the form of permissible testimony; impeachment governs credibility once they testify. Students wrongly exclude a lay witness’s everyday inference — speed, intoxication — as “incompetent” when it is admissible lay opinion under Rule 701. Memory hook: Perceive, Recall, Communicate, Oath — the four competency pillars.