In order to better understand the extent to which operationalizations of response to intervention (RTI) overlap and agree in identifying adequate and inadequate responders, an existing database of 399 first grade students was evaluated in relation to cut-points, measures, and methods frequently cited for the identification of inadequate responders to instruction. A series of 543 2x2 measures of association (808 total comparisons) were computed to address the agreement of different operationalizations of RTI. The results indicate that agreement is generally poor and that different methods tend to identify different students as inadequate responders, although agreement for identifying adequate responders is higher. Approaches to the assessment of responder status must use multiple criteria and avoid formulaic decision making. (Contains 8 tables.)