A mixed methods research design combining quantitative and qualitative approaches will provide evidence of the reliability and validity of the information collected, and the feasibility of using tablet portfolios for supporting instructional improvement efforts.
Advanced quantitative methods include multifaceted generalizability theory, factor analysis, and hierarchical linear models, which were used to assess the properties of the portfolio data and their relation to other teacher measures (e.g. ATLAST test of pedagogical content knowledge, teacher background survey) and student outcomes (e.g. CA Standards Science Test, course grades, and a survey of student’s attitude towards science in their classroom ). This evidence was complemented with in-depth qualitative analyses of the contents of tablet portfolios, and debriefing interviews with participant teachers and raters, as well as district personnel in charge of teacher induction.