N.Y. RPT Law § 1262

§ 1262. Manner by which ratios shall be determined. In determining\nratios pursuant to this article, the commissioner shall, for the last\ncompleted assessment rolls and the four preceding assessment rolls,\ndetermine the ratios of assessed valuation to full valuation as of the\nfirst day of January of the fiscal year for which the ratios are\napplicable. Each ratio shall be determined on the basis of the market\nvalue survey completed pursuant to article twelve of this chapter and\nfor which the valuation date is the first day of January of each\napplicable year. In the event that a market value survey has not been\ncompleted based upon each such valuation date, the commissioner shall\ndetermine the ratios in the following manner:\n (a) compute the ratios of assessed valuation to the full valuation of\ntaxable real estate on the basis of market value surveys completed\npursuant to article twelve of this chapter;\n (b) on the basis of the ratios computed pursuant to subdivision (a) of\nthis section, project increases or decreases in the ratios for years for\nwhich the information has not been developed pursuant to article twelve\nof this chapter;\n (c) avail itself of appropriate market value information appearing in\nits office or acquired in the discharge of its duties pursuant to this\nchapter.\n