This research study developed a value-added instructional improvement analysis model. North Carolina state testing results were used in regression and residual analyses of student achievement. This analysis allowed for identification of the "most effective" and "least effective" biology teachers in Wake County Public Schools (WCPSS). The study found that the "most effective" biology teachers were focused on the delivery of biology instruction; resisted distractions from their classroom efforts; maximized student use of class time; studied and planned with other teachers using the North Carolina Biology Standard Course of Study; focused all student time on the Standard Course of Study goals; carefully planned teacher controlled student activities; and used data to guide their instructional practice. [Contributing Staff: David Holdzkom, Brad McMillen, and Michael Tally.]