Karsten Krauskopf, Karin Forssell

• In an effort to understand teachers' technology use, recent scholarship has explored the idea of technological pedagogical content knowledge (TPCK or TPACK). Many studies have used self-reports to measure this knowledge (SR TPCK). Several studies have examined the construct validity of these assessments by analysing the internal relationships of the knowledge domains, but little attention has been paid to how SR TPCK relates to external criteria. We tackled this question of discriminant validity by reanalysing 2 data sets. We used correlation and multiple regression analyses to explore whether conceptually related constructs explain any variance in participants' SR TPCK. In Study 1, we applied this strategy to German pre-service teachers using technology use, attitudinal variables, and objective measures of teachers' knowledge of technology and pedagogy as external criteria. In Study 2, we examined measures of technology knowledge, experience, and pro-technology beliefs for in-service teachers in the United States. Across bothIn an effort to understand teachers' technology use, recent scholarship has explored the idea of technological pedagogical content knowledge (TPCK or TPACK). Many studies have used self-reports to measure this knowledge (SR TPCK). Several studies have examined the construct validity of these assessments by analysing the internal relationships of the knowledge domains, but little attention has been paid to how SR TPCK relates to external criteria. We tackled this question of discriminant validity by reanalysing 2 data sets. We used correlation and multiple regression analyses to explore whether conceptually related constructs explain any variance in participants' SR TPCK. In Study 1, we applied this strategy to German pre-service teachers using technology use, attitudinal variables, and objective measures of teachers' knowledge of technology and pedagogy as external criteria. In Study 2, we examined measures of technology knowledge, experience, and pro-technology beliefs for in-service teachers in the United States. Across both studies, a sizeable amount of the variance in SR TPCK is explained by teachers' prior technology use and pro-technology attitudes. In contrast, fact-based tests of technology and pedagogy are distinct from SR TPCK. We discuss implications for these findings and argue that researchers should gather complementary measures in concert.…