In making its determination, the panel shall be mindful of the legislative purpose enumerated in RCW 41.80.300 and, as additional standards or guidelines to aid it in reaching a decision, shall take into consideration the following factors:

(1) The constitutional and statutory authority of the employer;

(2) Stipulations of the parties;

(3) Comparison of the hours and conditions of employment of personnel involved in the proceedings with the hours and conditions of employment of like personnel of like employers of similar size on the west coast of the United States;

(4) Changes in any of the circumstances under subsections (1) through (3) of this section during the pendency of the proceedings; and

(5) Such other factors, not confined to the factors under subsections (1) through (4) of this section, that are normally or traditionally taken into consideration in the determination of matters that are subject to bargaining under this chapter.