(1) All relevant evidence, including hearsay, is admissible if, in the opinion of the board, it is the kind of evidence that a reasonably prudent person is accustomed to relying on his or her business affairs. The board may exclude evidence for constitutional or statutory reasons or for a privilege recognized in the courts of this state. The board may also exclude evidence that is irrelevant, immaterial, or unduly repetitious.

(2) The board's experience, technical knowledge, competency, and specialized knowledge may be used to evaluate evidence.

(3) If not inconsistent with subsection (1) of this section, the board may rely on, but will not be bound by, the Washington rules of evidence.

(4) Copies or excerpts of documentary evidence may be submitted instead of the original evidence.