“…Experts agree that acceptable levels of comprehension occur when the reader knows at least 90 to 95 percent of the words in the text (Hirsch, 2003). In fact, many researchers hypothesize that the "fourth-grade slump," a sharp decline in reading scores which tends to occur between the third and fourth grades, particularly for low-income students, is actually the result of significant deficits in these students' vocabularies (Chall, Jacobs, & Baldwin, 1990). Usually, during the third to fourth grades, reading assessments move away from evaluating early reading skills (e.g., decoding, fluency) and, instead, measure reading comprehension to a much greater degree than in previous grades.…”