N.H. Rev. Stat. Ann. § 76:16-f

If an abatement is granted under RSA 76:16, RSA 76:16-a, or RSA 76:17, with a determination of market value, the market value of the property for a given tax year shall be equalized by multiplying the market value of the property by the previous tax year's median ratio as determined by the department of revenue administration under RSA 21-J:3. The market value of the property shall be equalized at 100 percent in any tax year for which the municipality conducts a full reassessment in accordance with RSA 75:1 and RSA 75:8-a.