Property tax caps have been very much in the news in the Northeast. A 2 percent cap was passed by the legislature and signed by Governor Chris Christie in New Jersey, while Governor David Paterson's 4 percent cap still awaits approval in neighboring New York. The experience of Massachusetts, which has operated for three decades under its Proposition 2½ tax limit, has been cited frequently; both supporters and opponents of tax caps have drawn ammunition from the Massachusetts experience. But the most important lesson from the Bay State lies in the practical implementation of a tax cap: be sure to limit collections, not assessments. So writes Joan Youngman, senior fellow and chair of the Department of Valuation and Taxation at the Lincoln Institute, in this op-ed essay on property tax caps which appeared in The Journal News in Westchester County, New York on Sunday. At first glance, it might seem unimportant whether taxes are capped by limiting collections, tax rates, or assessed values. Any of these can reduce tax burdens, because collections are a product of the tax rate and the assessed values. But assessed values are the key because they distribute the tax burden among taxpayers, Youngman writes. When assessments reflect market values, taxpayers are able to judge the accuracy of their tax bills, and homeowners are typically very well informed about local property prices.