Nassau County Comptroller Elaine Philips’ office released a report saying former Democratic Executive Laura Curran’s controversial property reassessment relied on “flawed data.”

The report followed a yearlong audit of the 2020-2021 reassessment of the county’s approximately 386,000 residential and 37,000 commercial properties. 

In the report, the Department of Assessment was criticized for not fixing property information and data weaknesses reported to the agency by two expert evaluation firms, Standard Valuation Services and Michael Haberman Associates Inc., hired by then-Executive Ed Mangano in 2015. 

The two firms found the Department of Assessment was still using flawed data after it failed to fix the errors they flagged before the 2020-2021 reassessment.

“Prior to performing the 2020/21 Reassessment, the DofA did not fix property information and data weaknesses reported to them by SVS and MHA,” the report said. 

Additionally, the report said the Curran administration made unexplained changes to the assessment roll that “did not allocate sufficient time to correctly perform the reassessment” and the lack of cyclical reassessments prior to the 2020-2021 school tax year led to a jump in assessed values.

Philips last year announced her office was auditing the county’s Department of Assessment over the handling of the countywide assessment. 

The audit covered the department’s application of the phase-in, which went into effect in the 2020-21 school tax year, and the assessment rolls for the years 2021 to 2024.

According to county data, 65 percent of Nassau County homeowners received increases in their school taxes compared with 35 percent who received reductions in December 2020.   Curran called for the reassessment of more than 385,000 homes in 2018 after the county’s assessment roll had been frozen since 2008. 

During that period, thousands of residents filed grievances on the value of their homes, winning reduced assessments and shifting the tax burden to others who did not challenge their assessments.

“Taxpayers in Nassau County have the right to expect fair and equitable property valuations, conducted with transparency,” Philips said in a statement. “Restoring trust in government is among my highest priorities, and integrity and fairness in assessed values are among our residents’ top concerns. This review of the 2020/21 Reassessment – which has implications through 2025 and beyond – sheds light on a deeply flawed process and makes recommendations for the improvement of the county’s property assessment process going forward.” 

Curran was elected executive in 2018, then lost her re-election bid to current Republican Supervisor Bruce Blakeman, who was critical of the reassessment process after announcing his candidacy.

Recommendations in the report include consistently reviewing and updating data for properties, allocating sufficient time to perform quality control reviews of property valuations, maintaining a clear audit trail and maintaining accurate physical descriptions of properties.