A sign for assessment information is pictured at the Nassau...

A sign for assessment information is pictured at the Nassau County Department of Assessment in Mineola on Oct. 3, 2018. Credit: Barry Sloan

Lynbrook homeowner Dennis Duffy filed suit Wednesday to force Nassau County Executive Laura Curran to reveal the computer formula used to calculate home values included in her countywide property tax reassessment.

The county had denied Duffy’s repeated requests for the algorithm used to develop his home’s new assessment. Officials characterized it a “trade secret” exempt from disclosure because the formula was embedded in the software of a consultant hired for the reassessment.

But Duffy argues in his lawsuit — filed in state Supreme Court less than a week before Tuesday’s deadline for Nassau’s more than 424,000 residential and commercial property owners to challenge their new assessments — that the county has not explained how it derived the market value of his home, which helps set the amount of property taxes he pays.

“I am not asking how the software does its calculations or for a copy of the computer code,” Duffy said in a statement. “I am asking Nassau County to explain how it determined my assessment so I can make an informed decision whether I agree and whether I should spend time and money filing a grievance.”

Cameron Macdonald, executive director of the Albany-based Government Justice Center, which is representing Duffy without charge, also called it “important to remember, Nassau might have a decent number of people who are not originally from the U.S., who might really be hesitant to go protest against their government based on where they’re from. I think there’s probably a substantial population of Nassau County residents who come from a cultural background who just don’t go confront their government.”

According to its website, the nonprofit, nonpartisan center provides "pro bono representation and legal services to protect the rights of New Yorkers in the face of improper action by state or local governments."

The lawsuit asks the court to declare Nassau acted unlawfully, in violation of the state’s Freedom of Information law, and to order the county to release the requested formula and pay attorney fees and litigation costs.

“The county has demonstrated a clear disregard of its responsibility to be open and transparent,” Duffy said in legal papers. “Litigation should not be required to compel disclosure of records so fundamental to property owners understanding the bases of their assessments.”

The state Committee on Open Government issued an advisory opinion last month saying, “neither the vendor nor the county should be permitted to claim trade secret status” because the algorithm is used to make “important government decisions.”

Curran spokeswoman Chris Geed said in an email that the county executive “is committed to transparency and open government. The formula that (Duffy) is requesting is the property of the vendor, not Nassau County. The County has no legal right to release this information.”

Hempstead Town Tax Receiver and town supervisor candidate Don Clavin, a Republican who hosted a news conference with Duffy last month, said, “It's outrageous that taxpayers have to sue the Nassau County executive and the assessor to receive the mathematical formula used to determine the amount of taxes that they pay. This is a complete opposite of transparency.”

According to the lawsuit, Nassau uses a “calculation ladder” with 30 unexplained adjustment factors to develop assessments and also lists comparable home sales without saying how the sales were selected.

The suit says the ladder at first omitted any bathrooms when calculating Duffy’s assessment. It also used a comparable  home sale described as having the same 1,752 square feet of living area as Duffy's home, “but an internet search reveals the property was advertised within the last two years as having recently renovated 2,700 square feet of space.”

The lawsuit describes an algorithm as essentially a manual that tells the computer what steps to take and calculations to use in developing an assessment. It contends the county offered no proof that vendor, Thigman & Associates, had asserted trade secret protection over the algorithm embedded in its “Prognose” software.

Duffy said in an email, “It is apparent to many that the process used to determine our new assessments is flawed. Hopefully, when the court requires the county to release the formula it used, the errors in that formula will be observed and corrected and new assessments produced based on the corrected formula. It’s a real puzzle as to why a reassessment fueled by a desire to be fair has been conducted in secrecy.”

Macdonald said the case was assigned to Justice Leonard Steinman with a return date of May 22.

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