''Unfair Prejudice'' Legal Definition (Evidence)
In Old Chief v. United States, 519 U.S. 172, 117 S. Ct. 644, 650, 136 L. Ed. 2d 574 (1997), the Court considered the admissibility of evidence under Rule 403:
The principal issue is the scope of a trial judge's discretion under Rule 403, which authorizes exclusion of relevant evidence when its "probative value is substantially outweighed by the danger of unfair prejudice, confusion of the issues, or misleading the jury, or by considerations of undue delay, waste of time, or needless presentation of cumulative evidence." FED. R. EVID. 403. Old Chief relies on the danger of unfair prejudice.
The term "unfair prejudice," as to a criminal defendant, speaks to the capacity of some concededly relevant evidence to lure the factfinder into declaring guilt on a ground different from proof specific to the offense charged. See generally 1 J. Weinstein, M. Berger, & J. McLaughlin, Weinstein's Evidence, P 403 (1996) (discussing the meaning of "unfair prejudice" under Rule 403).
So, the Committee Notes to Rule 403 explain, "'Unfair prejudice' within its context means an undue tendency to suggest decision on an improper basis, commonly, though not necessarily, an emotional one." Advisory Committee's Notes on Fed. Rule Evid. 403, 28 U.S.C.App., p. 860.
The Court of Criminal Appeals favors "admission of relevant evidence and implies a presumption that relevant evidence will be more probative than prejudicial." See generally TEX. R. EVID. 403 . In Brimage v. State, 918 S.W.2d 466, 505 (Tex. Crim. App. 1994), cert. denied, 519 U.S. 838, 117 S. Ct. 115, 136 L. Ed. 2d 66 (1996), the Court of Criminal Appeals held relevant evidence, which is not inflammatory or prejudicial and assists the jury in deciding a case is admissible.
The court has also held that Rule 403 requires exclusion of evidence only when there exists a clear disparity between the degree of prejudice of the offered evidence and its probative value. See Joiner v. State, 825 S.W.2d 701, 708 (Tex. Crim. App.1992) and Brimage, 918 S.W.2d at 506.