Ind. Code § 22-6-2-10
It shall be the duty of the board to make written findings of fact, and to promulgate a written decision and order, upon the issue or issues presented in each case. In making such findings the board shall consider only, and be bound only, by the evidence submitted by the parties to the dispute. When a valid contract is in effect defining the rights, duties and liabilities of the parties with respect to any matter in dispute, the board shall have power only to determine the proper interpretation and application of the contract provisions which are involved. Where there is no contract between the parties, or where there is a contract but the parties have begun negotiations looking to a new contract or amendment of the existing contract, and wage rates or other conditions of employment under the proposed new or amended contract are in dispute, the board shall establish rates of pay and conditions of employment which are comparable to the prevalent wage rates paid and conditions of employment maintained for the same or similar work of workers exhibiting like or similar skills under the same or similar working conditions, by like public utility employers, if any, in the same labor market area, and if none, in adjoining labor market areas within the state of Indiana, and which in addition thereto bear a generally comparable relationship to wage rates paid and conditions of employment maintained by all other employers in the same labor market area. The board shall determine in each case, based upon the evidence presented and received by the board, what constitutes in that case "the same labor market area" or "adjoining labor market areas in the state of Indiana;" and where an employer has more than one (1) plant or office and some or all of such plurality of plants or offices are found by the board to be located in separate labor market areas, the board shall establish separate wage rates or schedules of wage rates, and separate conditions of employment, for all plants and offices in each such labor market area. In establishing wage rates the board shall take into consideration the overall compensation presently received by the employees, having regard not only to wages for time actually worked but also to wages for time not worked, including (without limiting the generality of the foregoing) vacations, holidays, and other excused time, and all benefits received, including insurance and pensions, and the continuity and stability of employment enjoyed by the employees.
IC 22-6-2-10