This research-in-progress paper examines the effects of different measurement methods for learning success with respect to the empirical evaluation of technology-mediated learning (TML). We argue that the use of self-reported data for the major dependent variable of TML, learning success, is insufficient and a major validity threat of past research results; thus, we examine the effect of employed measurement methods in TML against the background of common method variance. We are currently conducting a study on the antecedents of learning success measured by three different approaches that include self-reported learning and objective learning success. By analyzing the data, we are able to investigate how different measurement approaches to learning success impact research findings. Our contribution to theory and practice is an assessment of the validity of self-reported learning success measures and the impact of different measurement approaches for the relationships in a TML model.