The introduction in 1997 of "substituted judgment" as a guiding principle for guardian decisions was a key contribution of the UPC to guardianship reform. The current UPC section 5-314(a) instructs guardians to "consider the expressed desires and personal values of the ward" when making decisions and to "at all times...act in the ward's best interest." This dual mandate for guardian decisions was intended to promote the self-determination interests of incapacitated adults. This article argues that in practice the standard has failed to achieve this goal. It analyzes the shortcomings of UPC Section 5-314(a) and other statutory decision-making standards and offers an improved decision-making model. Frolik and Whitton propose reform of Section 5-314(a) to provide better guidance for guardians, and to harmonize the standard for guardian decisions with other surrogate decision-making standards within the UPC.