(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 in the conduct of his or her business affairs. The board may exclude evidence for constitutional or statutory grounds, or for evidentiary 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) Documentary evidence may be submitted in the form of copies or excerpts.

(4) If not inconsistent with subsection (1) of this section, the board may refer to, but is not bound by, the Washington state court rules of evidence.