Sir.—We enjoyed the article by Blackman et al,1 finding it thought provoking and interesting. However, we have a number of concerns about the study's methods and conclusions, as described below.
The authors observed correctly that learning disabilities can rarely be detected in 4- and 5-year-old children. The authors also noted that deficits in prekindergarten skills are not always manifested by the time children reach third grade. Both observations are well founded.2 However, the authors use these two observations to conclude that prekindergarten assessment is not predictive. This conclusion is incorrect.
Prekindergarten screening is highly predictive, but only of performance in kindergarten.3 Prekindergarten screening tests are not designed to predict long-term educational outcome but rather to help identify students who are likely to have difficulty with the kindergarten curriculum because they have not mastered essential prerequisite skills (eg, knowledge of letter names and counting).4 By identifying