23 Association of Research Libraries Research Library Issues 290 — 2017 Input measures are the easiest to collect and compare, of course: e.g., number of sessions and number of participants over time, possibly benchmarked against other institutions. Although input measures are relationally useful (how are we doing compared to past periods or to our peers?), there has been a lot of interest in developing outcome measures for more meaningful evaluation. Reaccreditation guidelines in higher education have advanced practices of learning outcomes assessment, so measuring student skills against learning goals has become more widespread. It is relatively easy to develop outcomes-based assessment for the ACRL standards for information literacy competency by measuring the degree to which the students are able to meet the learning goals of locating, evaluating, and effectively using information pre- and post- library instruction. This kind of outcomes-based assessment of library instruction is universally accepted theoretically, even if not yet practiced everywhere. Creating an outcomes-based assessment methodology and constructing relevant instruments to measure whether students have mastered and can transfer knowledge related to the six information literacy frames will probably take longer and may very well reach the impasse that seems to define the current debate around correlating library instruction (or use of the library in general) to student learning outcomes.5 All of the frames are going well beyond library instruction and, in that sense, it would be difficult to argue for any correlation, much less causation, between library instruction and critical thinking development, for instance. While useful learning outcomes–based assessment measures that are grounded in the Framework for Information Literacy are the aspirational goal, critical thinking, and especially growth in critical thinking over time, is notoriously difficult to assess. In the meantime, as an active participant in the process of higher education, the academic library is required to evaluate the success of library instruction, both for service improvement and resource allocation, or as a performance indicator for library instructors.