The 'SmartMobile' research project is directed to design and develop tools to help mobile companies view and analyze data related to the usage and performance of their applications and services. In this paper we focus on one of the main tools that were developed - MATE (Mobile Analysis Tool for usability Experts). MATE is designed to highlight potential usability problems in specific mobile applications, tasks and screens. This is done by extracting and aggregating relevant usage and performance metrics from real customers using their mobile devices. Subjective metrics received from usability tests may be inserted to MATE in order to compare objective and subjective metrics per scenario and per task. Usability evaluations performed by experienced usability experts strengthened the necessity of this tool as an important complement to usability testing.