We examined the extent to which use of a technology-enhanced continuous progress monitoring system would enhance the results of math instruction, examined variability in teacher implementation of the program, and compared math results in classrooms in which teachers did and did not use the system. Classrooms were randomly assigned to within-school experimental and control groups. Participating students were pre- and post-tested using two standardized, nationally normed tests of math achievement. When teachers implemented the continuous progress monitoring system as intended, and when they used the data from the system to manage and differentiate instruction, students gained significantly more than those for whom implementation was limited or nil. Failure to take into account intervention integrity would have made it look like continuous progress monitoring did not enhance math results. (Contains 5 tables.)