Newsday analyzed nearly 137,000 residential property tax assessment appeals filed with Nassau County's Assessment Review Commission for the 2015 tax year, which includes the October 2014 school tax bills and the January 2015 general tax bills. The analysis focused on challenges that resulted in a settlement and a reduction in a home's value between the tentative and final assessment rolls. Because the commission sometimes considers a case "settled" even when a challenger agrees that no reduction is warranted for their property, some homes may have been reduced for other reasons, such as those assessed for Superstorm Sandy damage during the grievance period. Sandy struck Long Island after Mangano implemented his program, so the jump in settlement cases are not attributable to the storm.

Newsday's story doesn't address the firms that settled fewer than 1,000 cases. They typically had settlement rates below the larger firms and pro se challengers. Representatives with some of those smaller firms, as well as county officials, agreed that this group made for a poor comparison with the large firms and pro se cases because they handle small caseloads and often specialize in litigation -- two factors making them more likely to reject the commission's offers and take their cases to court.