(dissenting). I respectfully dissent and would affirm the Appellate Division order. The side letter agreement is the product of a negotiation between the New York State Public Employees Federation, AFL-CIO (PEF) and respondent New York State Governor’s Office of Employee Relations. Both of those sophisticated entities are well schooled in the art of negotiation. To say that PEF implicitly agreed to a 25% wage reduction strains credulity.
The majority essentially concludes that because the side letter incorporates more than 50 articles from the 1995-1999 collective bargaining agreement (CBA) between PEF and the State regarding employees in the Professional, Scientific and Technical Services Unit, the compensation reduction now in question necessarily was negotiated by PEF and the State— even though it is undisputed that neither those articles nor the balance of the side letter considers that issue. In doing so, the majority supposes that because many parts of the CBA were incorporated into the side letter, and because the side letter otherwise considers salary increases, the compensation reduction now at issue must have been contemplated by that agreement.*
Although respondent New York State Public Employment Relations Board (PERB) is entitled to “deference in matters *508falling within its area of expertise” (Matter of Town of Islip v New York State Pub. Empl. Relations Bd., 23 NY3d 482, 492 [2014] [internal quotation marks omitted]), and although this Court generally is reluctant to disturb a determination of PERB (see Matter of Poughkeepsie Professional Firefighters’ Assn., Local 596, IAFF, AFL-CIO-CLC v New York State Pub. Empl. Relations Bd., 6 NY3d 514, 522 [2006]), I do not presume that the adoption of many aspects of the CBA and the side letter’s consideration of pay increases means that the subject pay decrease was negotiated here.
Indeed, the deference afforded PERB, while “great” (.Matter of Town of Southampton v New York State Pub. Empl. Relations Bd., 2 NY3d 513, 520 [2004]), is not unbounded. Respondent New York State Racing and Wagering Board, the employer of the affected workers, relies on an affirmative defense of duty satisfaction, that is, a defense for which it bears the burden of proof (see Siegel, NY Prac § 223 at 381 [5th ed 2011]). I cannot conclude that such affirmative defense has been satisfied where, as here, the parties to the negotiation carefully noted the items that had been negotiated and intentionally omitted therefrom the subject matter that is now in dispute.
Said another way, in assessing the side letter we should not confuse quantity with specificity so as to conclude that the absent item is present. Under these circumstances, I cannot agree that an item absent from an agreement containing a comprehensive explanation of negotiated items prepared by sophisticated parties somehow is encompassed by that compact. For those reasons, I agree with the Appellate Division that PERB’s determination that the side letter embraced the pay reduction in question is arbitrary and capricious, and I respectfully dissent.
Judges Pigott, Rivera, Abdus-Salaam and Garcia concur; Judge Fahey dissents in an opinion; Judge Stein taking no part.Order reversed, without costs, and judgment of Supreme Court, Albany County, reinstated.
This case is governed by the Taylor Law (Civil Service Law § 200 et seq.), which, in matters within its purview, imposes a “strong and sweeping” obligation (Matter of Board of Educ. of City School Dist. of City of N.Y. v New York State Pub. Empl. Relations Bd., 75 NY2d 660, 667 [1990] [internal quotation marks omitted]) to “collective[ly] bargain! ] over all ‘terms and conditions of employment’” (Matter of Patrolmen’s Benevolent Assn, of City of N.Y., Inc. v New York State Pub. Empl. Relations Bd., 6 NY3d 563, 572 [2006] [emphasis *508added], quoting Civil Service Law § 204 [2]; see Matter of New York City Tr. Auth. v New York State Pub. Empl. Relations Bd., 19 NY3d 876, 879 [2012]).