The director of personnel shall make investigations and report to the personnel board upon all matters touching the enforcement and the effect of this part and the rules and regulations prescribed thereunder. He or she may inspect all places of employment and services affected by this part in order to ascertain and advise with the heads of the various departments concerning their methods of handling those matters affecting employees in the service, such as hours of work, attendance, training, working conditions, morale, and in order to ascertain whether this part and all such rules and regulations promulgated thereunder are obeyed. The director of personnel in the course of such investigations, shall have the power to administer oaths, subpoena, and require the attendance of witnesses, and the production of books, papers, documents, and accounts pertaining to the subject under investigation. All hearings and investigations made by the director of personnel shall be governed by this part and by rules of practice and procedure adopted by the personnel board, and in conducting such investigations he or she shall not be bound by the technical rules of evidence. No informality in any proceeding or in the manner of taking testimony by the director of personnel shall invalidate any order, decision, rule, or regulation made by him or her, and approved or confirmed by the personnel board.