Researchers have recently used traditional item response theory (IRT) models to measure mathematical knowledge for teaching (MKT). Some studies (e.g., Hill, 2007; Izsak, Orrill, Cohen, & Brown, 2010), however, have reported subgroups when measuring middle-grades teachers' MKT, and such groups violate a key assumption of IRT models. This study…

Profile analyses were used to investigate differences in the self-efficacy growth of teachers with more and less mathematics background as the teachers participated in professional development across two summers. Professional development activities were associated with increases in teachers' self-efficacy; however, without considering mathematics…

Understanding frames of reference is critical in describing planetary motion and learning astronomy. Historically, the geocentric and heliocentric models were defended and advocated against each other. Today, there are still many people who do not understand the relationship between the two models. This topic is not adequately treated in astronomy…

The purpose of this study was to investigate and describe how middle school mathematics teachers "make meaning" of proofs and the process of proving in the context of their classroom practices. A framework of "making meaning," created by the researcher, guided the data collection and analysis phases of the study. This framework…