Systematic studies on effectiveness of in-service teacher professional development (PD) are important for science education research and practice. Previous studies mostly focus on one certain aspect of the entire program, for example, effectiveness of PD on improvement of teachers' knowledge or students' learning outcomes. This study, however,…

Freshmen with declared life-science majors typically matriculate with a determination to succeed. However, inadequately-prepared students are easily overwhelmed and at risk of abandoning their aspirations for a STEM career. The investigator designed and taught weekly recitations for approximately 850 students during a five-year span, and…