This report presents the final results of the evaluation that RAND conducted for the Army Medical Department as part of the demonstration for the low back pain practice guideline, which was conducted in 1999 and 2000. This first demonstration to field test methods for implementation of clinical practice guidelines (regarding low back pain) yielded rich insights. The performance of the demonstration and control Army health facilities on the six chosen indicators for acute low back pain care varied significantly at baseline (the six month period before the facilities started working with the guideline). Introducing the guideline had few measurable effects on those measures. However, the demonstration made a considerable contribution to improvements in methods for subsequent guideline demonstrations, and ultimately, for implementation of the low back pain guideline in all Army health facilities as of January 2000.