The ABB business unit in this study develops software for power systems applications and will be identified in the remainder of this paper as ABB MVPower. This business unit decided in January of 2003 to start a software process improvement (SPI) initiative and committed to have the initiative running for three years. Hence, the data analysed is aligned with this timeline. The sponsor for the SPI initiative was the site manager. He vocally expressed strong support for the SPI initiative and identified a change agent who was a project leader from the software development organization.