an inference or conclusion drawn from facts observed.

General Rule
Witnesses must give the facts and not their inference, conclusions,
or opinions.

The opinion of a witness is not admissible.


   Expert Witness
1. On a matter requiring SPECIAL knowledge, skill, experience or
   training which he is shown to possess

   Ordinary Witness
2. The identity of a person about whom he has adequate knowledge
3. A handwriting with which he has sufficient familiarity
4. The mental sanity of a person with whom he is sufficiently
5. The witness impressions of the emotion, behavior, condition,
   or appearance of a person

People vs. Adoviso (1999)
Polygraph test has not as yet attained scientific acceptance as a
reliable and accurate means of
ascertaining truth or deception.

Dilag Co. v. Merced (1949)
There is no precise requirement as to the mode in which
skill/experience shall have been acquired. Scientific study and
training are not always essential to the competency of a witness
as an expert. Knowledge acquired by doing is no less valuable
than that acquired by study.

Bar Exam 1994
At Nolan’s trial for possession and use of the prohibited drug,
known as “shabu:, his girlfriend Kim, testified that on a
particular day, he would see Nolan very prim and proper, alert
and sharp, but that three days after, he would appear haggard,
tired and overly nervous at the slightest sound he would hear.
Nolan objects to the admissibility of Kim’s testimony on the
ground that Kim merely stated her opinion without having been
first qualified as expert witness. Should you, as judge,
exclude the testimony of Kim?

Suggested Answer
No. The testimony of Kim should not be excluded. Even though
Kim is not an expert witness, Kim may testify on her
impressions of the emotion, behavior, condition or
appearance of a person.