Town of Greenburgh Aces Reassessment

Organization Profile

  • Industry: Municipal Government
  • Location: Town of Greenburgh, New York
  • Population: 90,000
  • Tyler Client Since: 2014
  • Parcels on Assessment Roll: 30,000
  • Tyler Products Used: CLT Appraisal Services™, iasWorld®


The Town of Greenburgh, New York, is located approximately 23 miles north of New York City in Westchester County. This Hudson River town enjoys a rich history that dates back to the American Revolution, and many of the area’s structures and monuments are found on the National Register of Historic Places.

While the locals treasure their storied past, the Town of Greenburgh assessor’s office was in possession of one historical collection that presented them with a lot of challenges — the hundreds of 60-year-old property record cards from the last town-wide reassessment.

Because there were never any follow-up reassessments, Town Assessor Edye McCarthy and her staff continued to recognize the valuations established during the 1956 initiative. That meant properties in the area were officially worth about 3.09 percent of their true, current market values.

Tyler was so responsive throughout the reassessment. When I called or dealt with anyone at any point in the day or night, they were quick to respond. If I asked them to attend a public meeting, Tyler was there, ready to address the crowd and answer any questions they may have had.

Edye McCarthy

Town Assessor, Town of Greenburgh, New York

The office staff also worked with an antiquated recordkeeping system that didn’t include a computer-assisted mass appraisal (CAMA) function or provide capabilities to capture digitized property files. Because their software couldn’t perform calculations, they had to complete assessments on a per-parcel basis in Microsoft® Excel. Assessors needed almost half an hour to value a single parcel.

The assessor’s office rarely reassessed properties. They could only inspect them when the town granted owners a building or demolition permit. Even then, there were limitations to adding a contributory value to the total assessment based on improvements made to the property or structure.

To add to the confusion, both taxpayers and the assessor’s office had to work with multiple layers of local government, a common practice with New York state municipalities. Six villages and several neighborhoods within Greenburgh hired independent assessors to appraise properties for their own tax rolls. Property values in those records often conflicted with the town’s.

Over time, taxpayers became more concerned about the inequity in property values caused by the inclusion of outdated and conflicting assessments. During the annual appeals process, property owners challenged 10 to 12 percent of the assessment roll. Commercial property owners often dealt with a backlog in their appeals, which meant they could contend with five to six years of contested valuations at a time. By the end of the annual appeals process, approximately $10 million in refunds were being paid out by the town, county, school, villages and fire districts every year.


Other nearby municipalities struggled with the same challenges as the Town of Greenburgh. Together, they formed the Multiple Municipal Reassessment Consortium (MMRC) to help build support for a new reassessment initiative among peers, politicians and taxpayers. The communities combined all their parcel counts into a unified group to achieve economies of scale. Then, the consortium invited companies to provide bids to reassess all the combined parcels.

McCarthy and her team secured the support they needed and partnered with Tyler’s CLT Appraisal Services to execute a town-wide reassessment. The CLT leadership team alone brought more than 200 years of experience to the table and put it to work to restore something that had been elusive to the Town of Greenburgh since 1956 — property valuations that were fair, accurate, equitable and easy to defend.

The town also began implementing Tyler’s iasWorld CAMA™ software — the industry’s most robust mass appraisal solution — to capture and work with the soon-to-be-updated property data.

The Town of Greenburgh’s assessor’s office and CLT sent brochures to taxpayers announcing the reassessment and upcoming town meetings. They also provided FAQ’s about the project.

CLT’s expert staff knew that providing ongoing information to the public would be essential, since much of the population had never been through a property reassessment. They distributed brochures in English and Spanish that announced the reassessment, explained Tyler Technologies’ role in it, provided FAQs and invited taxpayers to a series of public meetings held by the assessor’s office and the CLT team.

To kick off the town-wide reassessment, the team hosted a public meeting attended by more than 150 property owners. During the presentation, taxpayers learned more details about the process and had an opportunity to ask questions. The meeting was just the first of 60-plus gatherings. Throughout the reassessment, the assessor’s office and CLT met with realtors, rotary groups, homeowners’ associations and many others organizations, while also providing monthly updates to the town board.

The CLT team also launched an MMRC consortium website using iasWorld Public Access™ — an integrated solution of iasWorld that provides constituents with 24-hour access to local property assessment and valuation data. Taxpayers visited the site for news about the ongoing reassessment. They also gained confidence and a sense of security by reviewing the identities of data collectors, including their names, photos and license plate numbers. By launching the site, CLT helped data collectors gain easier access to properties and saved office staff time once devoted to fulfilling requests for information.

During the iasWorld CAMA implementation, the CLT team conducted software training for the assessor’s office staff, along with other assessors from affiliated communities within the MMRC. They also made the necessary adjustments to ensure the software could handle the unique needs of the Town of Greenburgh. Because there were no sketches in the old system, CLT created new ones for each property. They handled mapping and updated sales permit history, photography and other forms of data. As data collectors returned from the field, the team entered the new property information into the town’s new iasWorld CAMA solution.

The iasWorld team focused on adjusting the exemption functionality and calculations in the Assessment Administration (AA) function of iasWorld CAMA. AA is the core functionality that addresses the need to collect and store data and review exemptions.

As the basis for the regression models they were building for Greenburgh, the CLT team used models developed by Dr. Richard Borst, Tyler’s senior research scientist, for consortium member Ossining, New York. They worked closely with Borst to refine their base models and to conduct statistical analysis.

CLT introduced an MMRC reassessment website with individual pages for participating communities, including the Town of Greenburgh.

Together, they met with the assessor’s office to explain the philosophy behind regression modeling and discuss how it accounts for the many variables and differentials between two similar homes, such as pools, decks, outbuildings and finished basements. As a group, they determined neighborhood boundaries, which comps to select in each neighborhood, how many models to use, and which variables to consider and constrain.


In the end, the Town of Greenburgh assessor’s office, CLT Appraisal Services and the iasWorld team delivered a successful reappraisal initiative. For the first time in 60 years, McCarthy and her staff worked with property valuations that reflected 100 percent true market values. Town administrators also pledged to maintain values at 100 percent with regular reassessments.

By implementing iasWorld, the assessor’s office could calculate accurate and equitable property valuations in a quarter of the time it previously took. The staff enjoyed the flexibility of the new software and how the built-in models captured a more consistent base of values — making it much easier to explain and defend updated property values to taxpayers.

In a typical year, Town of Greenburgh property owners file 2,800 to 3,000 appeals from a total parcel count of 30,000. After the first town-wide reassessment in 60 years and the introduction of property valuations that reflected 100 percent market value, only 3,200 property owners filed appeals. Because the new valuations were so easy to defend, a larger number of appeals failed to move past the administrative phase. McCarthy anticipates that the volume of appeals will greatly decrease in the coming year.

The villages within Greenburgh also adopted the town’s new valuations, ensuring all local property records contain consistent values. Taxpayers are now saving approximately $120,000 a year because tax dollars are no longer needed to fund independent assessments.

As a testament to the accuracy of CLT’s property valuations, many homes that have gone up for sale since the reassessment are selling at prices that are surprisingly close to the values that the town staff and CLT’s expert team calculated.

The assessor’s office is also increasing transparency by providing unprecedented access to the town’s property inventory and valuations on the MMRC website. Taxpayers can review new property valuations, property characteristic overviews, sales history, sketches, photography and more.

McCarthy and her staff look forward to other benefits of the iasWorld CAMA solution, including the ease in which the state, county, school, village and town can complete needed reporting. All five entities can create reports at the same time, significantly speeding up this once time-consuming process.

The town anticipates that the successful reassessment initiative and the new iasWorld software will help it achieve long-term budget stability, reductions in assessment appeals and tax refunds and, most importantly, ongoing fairness and equity among valuations. Now, everyone pays their fair share in taxes in the Town of Greenburgh, New York.

CLT Appraisal Services Has Been Setting the Standard Since 1938

The Town of Greenburgh assessor’s office accomplished a successful reassessment project because they understood the importance of fair and equitable property valuations, transforming their accuracy and efficiency with the iasWorld CAMA solution and choosing an industryleading partner that has been conducting property reassessments across jurisdictions both big and small for nearly 80 years.

CLT Appraisal Services is the country’s only national mass appraisal services company with expert staff who specialize in appraisal services, property valuation, market modeling and analysis. CLT provides both traditional services — including data collection, data entry, valuation, review and appeals — and technologically driven services — including street-level imaging and CAMA sketch and data verification.

If Tyler software implementation is part of the jurisdiction’s solution, CLT won’t just collect and input property data. They provide their expertise and work alongside the appraisal and tax offices to identify and modify their Appraisal & Tax Solutions to meet the unique needs of the jurisdiction. The CLT team also understands the industry and has experience working in all brands of CAMA software. That means they can work with any line of software to ensure clients have the smoothest and most efficient reassessment process possible.

Case Study Highlights

  • Town partnered with CLT Appraisal Services for first town-wide reassessment in 60 years
  • Property valuations now reflect 100% true market values
  • By implementing iasWorld, the assessor's office is able to calculate accurate and equitable property valuations in a quarter of the time it previously took

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