This paper aims to contribute to the theoretical framing of Technological Pedagogical Content Knowledge (TPACK) by exploring how a measurement approach can be used to address the need to improve the prescriptive value of the framework. Building on and extending the work described in Saubern, Urbach, Koehler and Phillips (2019), this paper describes the development of an empirically derived qualitative description of increasing proficiency in TPACK Confidence and TPACK Usefulness. Using the results of a partial credit Rasch analysis of survey responses, five bands of proficiency in TPACK Confidence and five bands of proficiency in TPACK Usefulness were delineated and described. The study found that teachers at higher levels of TPACK proficiency more strongly believe in the value of using technology to facilitate deep thinking and learning and are more confident to use technology to support and facilitate deeper thinking and learning in and across curriculum areas than teachers with lower levels of proficiency. By providing a description of lower and higher proficiency and an inferred typical order of acquisition, the resulting construct maps can be used by researchers to help develop and test hypotheses about teachers' acquisition of TPACK and improve the validity and precision of TPACK survey tools and by teacher educators to better understand and evaluate the TPACK of student teachers and inform the development of teacher education curricula.
