Texas Penal Code - PENAL § 37.04. Materiality

(a) A statement is material, regardless of the admissibility of the statement under the rules of evidence, if it could have affected the course or outcome of the official proceeding.

(b) It is no defense to prosecution under Section 37.03 (Aggravated Perjury) that the declarant mistakenly believed the statement to be immaterial.

(c) Whether a statement is material in a given factual situation is a question of law.