This paper presents two studies adding validity evidence to the assessment of educational knowledge (EK) measured by a recently developed test. The first study compared the test scores of a large sample of graduates from academic teacher education with those of a sample of first-semester teacher students. Results indicate higher scores for graduates in the majority of the test's six domains. Additionally, we gained validity evidence based on response processes by conducting 46 cognitive interviews in Study 2. Participants with different professional backgrounds stated their response strategies while taking the knowledge test. Among other results, analyses revealed that graduates and advanced students in teacher education were often familiar with item topics and solved items mostly by retrieving academic knowledge from memory. Overall, results add to previously gained evidence suggesting that test scores can be taken to measure EK mainly gained by university studies.