The larger the sample size, the more precise the statistic. This is a general rule regardless of what statistic is being calculated or analyzed. One of the remedies the I.A.A.O. standards recommend for inadequate samples is “extending the period from which sales are drawn”. Supplemental sales will be added to the current year’s ratio study based on the following criteria as outlined in the New Hampshire Equalization Manual approved by the Equalization Standards Board.

  1. A trial study will be printed showing just the current year’s information prior to adding supplemental sales.
  2. Less than 20 valid sales were available in the time period from October 1 of the prior year to September 30 of the current year to conduct the ratio study for a municipality.
  3. Sales used in the municipality’s ratio studies from the prior two equalization years may be included.
  4. The supplemental sales to be included will be done in six-month increments. For example:
    • April 1, 2020 to September 30, 2020
    • October 1, 2019 to March 31, 2020
    • April 1, 2019 to September 30, 2019
    • October 1, 2018 to March 31, 2019.
  5. New assessments will be obtained for supplemental sales added to any municipality that has conducted a revaluation.
  6. All the sales from the six-month increment will be added until at least 20 valid sales have been included.
  7. A time trend analysis will automatically be done by the DRA.  If a municipality can provide documentation to support a different time trending, the DRA will consider the information provided.  In either case, a determination whether to apply the time trend or not will be made by the DRA.
  8. If there are not 20 valid sales available including sales from the prior two equalization years, the DRA will calculate ratio statistics based on the sales available, and use the best evidence available to determine the equalization ratio for a municipality.