The goal of the present study was to test three competing hypotheses about the nature of comprehension problems of students who are poor in reading comprehension. Participants in the study were first, second, and third graders, totaling nine cohorts and over 425,000 participants in all. The pattern of results was consistent across all cohorts: Less than 1 percent of first- through third-grade students who scored as poor in reading comprehension were adequate in both decoding and vocabulary. Although poor reading comprehension certainly qualifies as a major problem rather than a myth, the term specific reading comprehension disability is a misnomer: Individuals with problems in reading comprehension that are not attributable to poor word recognition have comprehension problems that are general to language comprehension rather than specific to reading. Implications for assessment and intervention are discussed.