Massachusetts General Laws Part I. Administration of the Government (Ch. 1-182) Ch. 79, § 35

The valuation made by the assessors of a town for the purposes of taxation for the three years next preceding the date of the taking of or injury to real estate by the commonwealth or by a county, city, town or district under authority of law may, in proceedings, brought under section fourteen to recover the damages to such real estate, the whole or part of which is so taken or injured, be introduced as evidence of the fair market value of the real estate by any party to the suit; provided, however, that if the valuation of any one year is so introduced, the valuations of all three years shall be introduced in evidence; and provided, further, that no such valuation shall be so introduced as such evidence unless within the five years preceding such taking or injury there has been a comprehensive revaluation of the real estate of the town and the valuation or valuations sought to be introduced are valuations assessed after such comprehensive revaluation.