A randomized experimental design with three levels of intervention was used to compare the effects of beginning reading interventions on early phonemic, decoding, and spelling outcomes of 96 kindergartners identified as at risk for reading difficulty. The three instructional interventions varied systematically along two dimensions--time and design of instruction specificity--and consisted of (a) 30 min with high design specificity (30/H), (b) 15 min with high design specificity plus 15 min of non-code-based instruction (15/H+15), and (c) a commercial comparison condition that reflected 30 min of moderate design specificity instruction (30/M). With the exception of the second 15 min of the 15/H+15 condition, all instruction focused on phonemic, alphabetic, and orthographic skills and strategies. Students were randomly assigned to one of the three interventions and received 108 thirty-minute sessions of small-group instruction as a supplement to their typical half-day kindergarten experience. Planned comparisons indicated findings of statistical and practical significance that varied according to measure and students' entry-level performance. The results are discussed in terms of the pedagogical precision needed to design and provide effective and efficient instruction for students who are most at risk.