I came across an interesting review by Joseph K. Torgesen in the American Educator that is relevant to recent discussions on Reading Recovery and Direct Instruction. You can find the article online, but I will limit myself to quoting just a few lines from the paper.
“Instruction for at-risk children must be more explicit than for other children. … Explicit instruction is instruction that does not leave anything to chance and does not make assumptions about skills and knowledge that children will acquire on their own. … Evidence for this is found in a recent study of preventive instruction given to a group of highly at-risk children during kindergarten, first grade, and second grade (Torgesen, Wagner, Rashotte, Rose, et al., 1999). Of three interventions that were tested on children with phonological weaknesses, the most phonemically explicit one produced the strongest growth in word-reading ability. In fact, of the three interventions tested, only the most explicit intervention produced a reliable increase in the growth of word-reading ability over children who were not provided any special interventions.(emphasis added) Other studies (Brown and Felton, 1990; Hatcher, Hulme, and Ellis, 1994; Iversen and Tunmer, 1993) combine with this one to suggest that schools must be prepared to provide very explicit and systematic instruction in beginning word-reading skills to some of their students if they expect virtually all children to acquire word-reading skills at grade level by third grade.