Many past development contracts have not included reliability development testing (Test, Analyze, and Fix (TAAF) methodology), instead relying on a reliability qualification test to demonstrate a numerical MTBF requirement. This approach has been ineffective in providing weapon systems with acceptable field reliabilities. Reliability development (TAAF) testing using simulated mission profile environments and emphasizing reliability growth has proven to be a more effective use of limited test resources, and has reduced the risk of transitioning systems from development to production.