There is strong and persuasive evidence that children who get off to a slow start rarely become strong readers (Stanovich, 1986). Early learning of the code leads to wider reading habits both in and out of school (Juel, 1988). 

     Wide reading provides opportunities to grow in vocabulary, concepts, and knowledge of how text is written. Children who do not learn to decode, do not have this avenue for growth. This phenomenon, in which the "rich get richer" (i.e., the children who learn to decode continue to improve in reading) and the "poor get poorer" (i.e. children who do not learn to decode early become increasingly distanced from the "rich" in reading ability), has been termed the Matthew Effect (Stanovich).

   "Well into the middle grades, children’s ability to understand text that is read aloud to them significantly exceeds their ability to understand the same text when reading on their own (Curtis, 1980). The bulk of this difference is traced to their difficulties in reading the words. Moreover poorly-developed word recognition skills are the most pervasive and debilitating source of reading difficulty (Adams, 1990; Perfetti, 1985; Share & Stanovich, 1995)."  (Marilyn Jaegar Adams is the author of "The Great Debate.")