Fed. R. Evid. 701

Opinion Testimony by Lay Witnesses

If a witness is not testifying as an expert, testimony in the form of an opinion is limited to one that is:

(a)

rationally based on the witness’s perception;

(b)

helpful to clearly understanding the witness’s testimony or to determining a fact in issue; and

(c)

not based on scientific, technical, or other specialized knowledge within the scope of Rule 702.

( Pub. L. 93–595, § 1 , Jan. 2, 1975 , 88 Stat. 1937 ; Mar. 2, 1987 , eff. Oct. 1, 1987 ; Apr. 17, 2000 , eff. Dec. 1, 2000 ; Apr. 26, 2011 , eff. Dec. 1, 2011 .)