It is often claimed that software development is negatively affected by infrequent, incomplete and inconsistent measurements; improving with the help of metrics is an obvious solution. Software testing provides opportunities for measurement that give organizations insight in to processes. Usability testing is part of the testing area, although it is not a commonly addressed area within software engineering, perhaps because of a split between qualitative and quantitative paradigms. We compare a usability testing framework called UTUM with principles for Software Process Improvement, and find areas of close agreement as well as areas where our work illuminates new characteristics. UTUM is found to be a useful vehicle for improvement in software engineering, dealing as it does with both product and process. Our work emphasises the importance of the neglected area of usability testing. Our experience also illustrates how the metrics have been tailored to act as a boundary object between different disciplines.