LibQUAL+[TM] data to date have not been subjected to the modern measurement theory called polytomous item response theory (IRT). The data interpreted here were collected from 42,090 participants who completed the "American English" version of the 22 core LibQUAL+[TM] items, and 12,552 participants from Australia and Europe who completed the "British English" version of the 22 core LibQUAL+[TM] items. Results suggest that the LibQUAL+[TM] protocol has psychometric integrity, that American English participants tend to be somewhat less critical of library service quality, and that students and faculty have fairly similar views of library service quality. (Contains 4 tables and 12 notes.)