The present disclosure relates to a method of obtaining at least one Key Performance Indicator (KPI) for a communication session (11) of a radio device (2). The communication session is moved from a first Radio Access Technology (RAT) (3a) to a second RAT (3b). The method comprises extracting first information about the communication session from at least a first log associated with the first RAT by filtering information relating to communication sessions which have moved between RATs from other communication sessions in the first log. The first information comprises a session identifier (ID) and a first time stamp associated with the communication session. The method also comprises extracting second information about the communication session from a second log associated with the second RAT by filtering information relating to communication sessions which have moved between RATs from other communication sessions in the second log. The first information comprises the session ID and a second time stamp associated with the communication session. The method also comprises merging the extracted first and second information with each other by means of the session ID and the first and second time stamps. The method also comprise determining the at least one KPI for the communication session based on the merged information.