This report outlines attempts to develop and evaluate a formal model of the "missing letter effect" (MLE), a phenomenon whereby literate human participants achieve differential performance in a letter detection task across word-type classes when performing the task while simultaneously reading for comprehension. Beginning with the observation that extant models fail to predict phenomena involving both the rate of detection failure and the mean detection response time, the report describes a new model that can predict these phenomena. The report continues by describing efforts to assess the new model's ability to predict additional phenomena related to the missing letter effect, including discussion of important statistical issues for fair evaluation.