Skip universal navigation

New York State Universal header

Skip to main content

Assessment equity in New York: Results from the 2016 market value survey

Summary of report

Section 1200 of the Real Property Tax Law requires that the Commissioner of Taxation and Finance monitor the equity of assessments in New York State in the context of its periodic market value surveys and report its findings to the Governor, the President Pro-Tem of the Senate, and the Speaker of the Assembly. The current report presents such an analysis, based on results from the 2016 survey.


Approximately 69 percent of the State's assessing units are indicated as having equitable assessment rolls. The number achieving overall equity had been rising steadily until the middle of the past decade (see Figure 1 in the report) and stands in dramatic contrast to the situation of about three decades ago when only about 10 percent had equitable assessments. However, in the last decade, equity levels retreated somewhat. It is believed that this reflects the influences of turbulent real estate markets in many areas, and the difficulty some assessors had in ensuring that their rolls reflect current market conditions. In the last few years, the trend in equity has stabilized, however.

A related positive trend has been the number of assessing units that have been updating their rolls on a frequent basis.  220 units (22 percent) have submitted cyclical reassessment plans committing to a regular cycle of reappraisal.  Although this is not a compulsory state requirement in New York State, the State's reassessment aid program has been recently modified to encourage the use of a four-year updating cycle.

Methodology of determination of findings:

The survey found that 461 assessing units (approximately 47 percent) implemented recent reassessment programs that could be used directly in determining 2016 municipal full value. For these assessing units, the survey process consisted of a review by Tax Department staff of the reassessment roll and the procedures and data used to conduct the reassessment program. In cases where the assessed values appearing on the roll represented a recent year other than 2016, they were adjusted to the statewide value standard of July 1, 2015 that was used in the survey. This review and trending process for assessing units with recent reassessments was first implemented for the 1996 market value survey and, for a substantial portion of the State, it has eliminated the costly sampling of rolls and appraisal of parcels that had been undertaken in prior surveys.

For the remaining approximately 53 percent of assessing units that did not have recent reassessments, samples of sales and appraisals and computer-assisted mass appraisal (CAMA) models were used to determine the local average level of assessment and variation around this average. Where reliable residential sales data reflecting the appropriate time frame were available, such sales were used to replace or augment individual parcel appraisals. CAMA techniques were employed where insufficient residential sales were available but local property inventories were satisfactory for statistical modeling purposes. For the non-residential property classes—generally characterized by greater heterogeneity and complexity—individual sampled parcels were appraised if the property class represented a significant component of the total value on the roll.

Uniformity of assessments on the sampled rolls was measured primarily through a statistic known as the Coefficient of Dispersion (COD). This statistic measures the extent of assessment "error" observed among the assessment ratios (assessed value divided by market value) of the sample parcels. Ideally, all ratios within an assessing unit (or, for New York City and Nassau County, within a property class) should be the same, indicating perfectly uniform assessments. However, unavoidable imperfections in valuation and estimation error require that some minimum level of variation be deemed acceptable. The amount of variation that is acceptable is a function of the type of property and the amount of market activity in a given community, with the most rural areas generally capable of attaining assessments that are less uniform than those attainable in urbanized areas, due to greater variability among properties and sparse market data for some or all property types.

Among the sampled assessing units, approximately 41 percent had COD estimates for the entire assessment roll that satisfied State guidelines, which in turn are based on standards established by the International Association of Assessing Officers (IAAO). In terms of residential property, where allowable COD levels are more stringent, 27 percent met the guidelines.