The chairman or board in making an investigation or inquiry or conducting a hearing shall not be bound by common law or statutory rules of evidence or by technical or formal rules of procedure, except as provided by this chapter; but may make such investigation or inquiry or conduct such hearing in such manner as to ascertain the substantial rights of the parties. Declarations of a deceased employee concerning the accident shall be received in evidence and shall, if corroborated by circumstances or other evidence, be sufficient to establish the accident and the injury.
New York Legal Code