Revaluations are performed periodically to assure that the burden of tax is distributed equitably and uniformly among property owners. State law requires municipalities to adjust assessments if a majority of market sale prices are more than 10% above or below the assessment. The Wisconsin Department of Revenue-Equalization Bureau monitors sales activity statewide and notifies each community if their assessments should be adjusted.
A Revaluation is a thorough review of assessed values throughout the City, when it is clear that open-market, arms-length real estate prices have increased or decreased enough to require that the assessments be adjusted to keep in step. During the Revaluation process, all assessed values are examined and adjustments are made where necessary to "catch-up" with market trends.
In Wisconsin, assessments are simply “snapshot” estimates of value whose chief purpose is to divide the burden of tax evenly and fairly between all properties in a community. Because they are only snapshots and may not be updated for several years, they ARE NOT good estimates of a property’s value TODAY.
As described by Chapter 70 of the Wisconsin statutes and the Wisconsin Property Assessment Manual, property assessments are calculated “en masse” or “as-a-group” in a process called Mass Appraisal. This mass appraisal process is based on analysis of Sale Prices, Construction Costs and Rents over a period of time.
Over time, there are high sales and low sales, but the assessor looks for the range of sale prices which is most common for each type of property to derive assessed values. It is important to remember that the assessor may only react to what happens in the market.
By design, Mass Appraisal does not address day-to-day fluctuations, but rather attempts to “smooth out” short-term variability by looking at the market over a period of years to understand how markets change overall.
This approach is very different from that used by private appraisers, who must rely on a few up-to-the-minute sales to satisfy risk-averse lenders, and may yield widely different results.