An assessment-sales analysis report has been prepared for the entire sampling of sales in a municipality as well as for each class of property (stratum singular, strata plural) a municipality has provided property-type codes for.  Stratified reports are available in the Assessment web portal for each municipality.

Each report includes the following:

  1. Equalization summary sheet: summarizes each stratum, and pertinent statistics for that stratum, as well as statistics for the overall sampling.
  2. Assessment review summary sheet: summarizes the three strata used for assessment review and whether they meet the assessment review guidelines adopted by the Assessing Standards Board. This sheet includes a graph that visually shows the statistics calculated for the assessment review process.
  3. Equalization Ratio (weighted mean): The weighted mean ratio will be used to adjust the modified local assessed value of your municipality in order to calculate the total equalized value of your municipality. The Assessing Standards Board adopted the use of the weighted mean for equalization only. It has not been adopted or recommended for use for any other purpose. If it can be determined that the weighted mean does not reflect an accurate measure of the municipality’s assessment level, another factor may be used. This is rare and generally occurs when there are insufficient sales in the ratio study.

    Alternate Ratio Methodology: The DRA may consider one of the following as an alternate ratio methodology to the weighted mean:
    • The DRA may consider other factors if the sampling of the sales is not generally reflective of the make-up of the municipality.  To challenge the representativeness of the ratio study, the municipality must provide data and information as to the correct representativeness and the ratio samples that fall into each category.
    • The DRA may consider separate assessment ratios for categories unduly affected by bi-modal or multi-modal assessments in a municipality.  Consideration will be dependent upon data and information provided by the municipality and verified by the DRA.
    • A municipality may request the DRA to consider using separate ratios for each stratum in their overall ratio study that contains at least 20 valid sales in a stratum, and shows a confidence interval, calculated with a 90% confidence level that is wholly outside the confidence level of other strata.

      Applying the separate ratios, when justified, the DRA will arrive at a single weighted overall ratio for the municipality based upon the separate ratios and the total assessed valuation of each. This single weighted overall ratio shall be used by the DRA to adjust payments-in-lieu-of-taxes, railroad tax monies, shared revenues, current use values and to compute the municipality’s total equalized valuation, where applicable.

      For each alternate ratio methodology listed above, the municipality must be able to provide the DRA with accurate assessed value information, subject to verification, for all properties within the strata.  Absent the necessary data and information, the weighted mean will be used.
  4. Statistics calculated as part of the ratio study: The report shows the statistics calculated prior to trimming for outliers and the statistics calculated after the trim procedure was used. Your final equalization ratio will be calculated after trimming. These statistics include, but are not limited to:
    • Measures of assessment level
      • Median ratio
      • Mean ratio
      • Weighted mean (aggregate) ratio
    • Measures of dispersion (equity)
      • Coefficient of dispersion
      • Price-related differential
        Note: Measures of dispersion are not used to adjust figures as part of the equalization process.        
    • Measures of reliability

      • Confidence levels (90%)

    • Miscellaneous information

      • Minimum and maximum sale price

      • Minimum and maximum ratio

      • Number of sales

  5. Sales used in the ratio study
  6. Sales not included in the ratio study and the reason why
  7. Frequency distribution for the sales not used in the ratio study
    For example: 2 family sales, 3 sheriff’s sales, etc.
  8. Time-trended Ratio Study (specific towns)
    The DRA will provide a time trended ratio study report for towns that meet specific criteria set forth in the 2020 Equalization Manual. This includes, but is not limited to, towns which have supplemental sales from prior equalization years added to it. The ability to produce a time-trended ratio study is dependent upon the ability to calculate a valid and reasonable time trending factor.

Unfortunately, in some cases, there were either no sales or not enough sales to give a reliable indicator of assessment or dispersion levels for a specific property type.

These reports are meant to be a tool to indicate to assessing officials the status of individual stratum. The Department of Revenue Administration is not suggesting, in any way, these ratios be used to factor classes of property up or down without further comprehensive study by the local assessing officials.

When reviewing the information for sales used in the overall sampling and sales used in the individual strata, it is important to remember you are looking at two different pictures.  The statistics for the overall sampling are calculated using all the sales in the sampling and present a picture of what is happening throughout the municipality.  The statistics for the individual strata are calculated using only those sales identified as being a part of that stratum and present a picture of what is happening in just the specific property type.  Sales that may be trimmed from the overall sampling may have been left in the stratum or vice versa

Assessment Review Process

The Assessing Standards Board has adopted the following statistical guidelines for municipalities in their year of assessment review:

  1. A median ratio between .90 and 1.10 with a 90% confidence level for the overall sample;
  2. An overall coefficient of dispersion (COD) of the municipality’s median ratio of not greater than 20.0 without the use of the confidence level;
  3. A median ratio for the three strata adopted by the Assessing Standards Board with a 90% confidence level within 5% of the overall median point estimate;

    For example: If a municipality’s median point estimate were 1.00, the 5% range would be from .95 to 1.05.  The median point estimates with 90% confidence intervals for the three assessment review strata would have to cross the .95 - 1.05 range.

  4. A price-related differential (PRD) between .98 and 1.03 with a 90% confidence interval.


The minimum sample size for calculating a statistic for any of the categories is eight.  Failure to calculate statistics due to insufficient sample size shall not have an adverse effect in meeting assessment review guidelines.