Early comprehension is an important, but not well-understood, contribution to early literacy and language development. Specifically, research regarding the nature of skills representative of early comprehension, including how they contribute to later reading success, is needed to support best practices to adequately prepare students. This article describes the process involved in the creation and refinement of the newly developed comprehension Individual Growth and Development Indicators (IGDIs 2.0). Two theoretical models of early comprehension are discussed to highlight the inherent complexity of this domain. Results of three studies are presented: Study 1 outlines the initial piloting process, Study 2 represents a larger-scale investigation, and Study 3 describes further field testing and reveals the final IGDI 2.0 comprehension candidate: Which One Doesn't Belong (WODB). Results indicated WODB out-performed the other candidate measures across psychometric and pragmatic criteria. The utility of the WODB task within a Response to Intervention (RTI) framework is also discussed. [This article was published in "Assessment for Effective Intervention" (EJ1050548).]