Projects combining agile methods with CMMI1 are more successful in producing higher quality software that more effectively meets customer needs at a faster pace. Systematic Software Engineering works at CMMI level 5 and uses Lean Software Development as a driver for optimizing software processes. Early pilot projects at Systematic showed productivity on Scrum teams almost twice that of traditional teams. Other projects demonstrated a story based test driven approach to software development reduced defects found during final test by 40%. We assert that Scrum and CMMI together bring a more powerful combination of adaptability and predictability than either one alone and suggest how other companies can combine them.