Research on monitored grid-connected PV systems can lead to an improved performance of PV systems. This view is based on monitoring results from PV systems in Western Europe which lag behind the expected values. However, current methods for analysing these systems do not allow to investigate the potential system eciency improvement on the basis of ยฎeld experience. Hence, we have developed a method for analysing monitored grid-connected PV systems which meets this need. In this method the common technical approach to analysing PV systems is broadened with an economic assessment. First an energy loss analysis of the PV system is made using its monitored data. In our analysis the energy loss eects in the PV system are split up by simulation. This provides a profound insight into the actual performance of the system. Next, measures to enhance the performance of the system are identiยฎed. The costs involved to improve the performance are analysed. Finally, the cost-eectiveness of the potential improvements is calculated. In this paper we will present our method TEAMS. Although we will not formulate strict rules, we will provide a well-deยฎned frame and structure for the application of the TEAMS method. It is shown that applying TEAMS contributes to improved transparency in the evaluation of monitored grid-connected PV systems.