Testimonial Evidence Flashcards
witness competency standard
testifying witness must be competent
* witnesses are presumed to be competent
ss c
witness competency
W must have:
1. **Personal knowledge: **based on W’s own perceptions
2. Memory: W must have ability to remember (not amnesia)
3. **Communication: **W must be able to relay perceptions (includes using translator)
4. **Sincerity: **W must take an oath or affirm to tell the truth
Dilution of any of these makes W less persuasive
exluding witnesses
upon party’s request, court must exclude W from hearing other W’s testimony
EXCEPT parties or party representatives (where party is non-person entity)
lay opinions
opinion testimony is admissible if it is:
1. rationally based: on W’s perception
2.** Helpful: **to the trier of fact (NOT legal conclusions)
3. Not expert: not based on scientific, technical, or other specialized knowledge
EX:
speed of car
emotional state of an individual
voice or handwriting recognition
sense recognition
intoxication
expert opinions
admissible only if:
1. Helpful: to trier of fact
2. Qualified: possesses special qualifications for opinion
3. Reasonable certainty: must believe in opinion to a reasonable degree of certainty
4. proper factual basis: based on facts (admitted evidence, personal knowledge, or inadmissible evidence properly relied upon like data, other testimony, experience)
5. reliable principals reasonably relied upon: (see scientific evidence)
expert opinions on scientific evidence
if expert opinion is based on science, courts also considers whether evidence is:
1. peer tested and capable of retesting
2. published
3. has a low error rate, and
4. reasonably accpeted in the field of study
scope of expert testimony
experts may render an opinion on any ultimate legal issue
EXCEPT D’s mental state in a criminal trial if it’s an element to crime or defense (leave for jury)
