The project aims to analyze the effectiveness of teachers and its determinants based on student-level achievement data from the German National Educational Panel Study (NEPS). Building upon the work of the first funding period, this project consists of three parts. First, we use the additional data to strengthen the statistical power of our estimation results, thereby allowing for more persuasive conclusions on teacher effectiveness and its determinants in Germany. Furthermore, we extend our previous study twofold. In the second part, due to the specific emerging structure of the NEPS data, we extend our previous estimation techniques that relied on two-year achievement gains to methods that will be based on one-year achievement gains. This is particularly interesting from a methodological point of view, as the standard of the literature is based on one-year gains. In addition, the comparison of these two estimation methods is critical for the assessment of our results of the first funding period and the potentially developed policy implications. In the third part, we want to exploit the considerably extended time dimension of the panel data by the end of the second funding period to improve the estimation methods. By then, the NEPS data will allow the cleansing of the variation in student performances of confounding factors. We want to divide this cleansed measure into a classroom and a teacher component, which will allow for a better identification of causal teacher effects on student achievement.