Library quality is no longer evaluated solely on the value of its collections, as user perceptions of service quality play an increasingly important role in defining overall library value. This paper presents a retooling of the LibQUAL+ survey instrument, blending the gap measurement model with perceptual congruence model studies from information systems management research. The new survey instrument redefines service desk assessment by taking into consideration the perspectives of both service users and of service providers, to help service providers gain a more robust sense of service quality.