Increasing secondary-level teachers’ knowledge in statistics and probability: Results from a randomized controlled trial of a professional development program

Reflecting growing emphasis on data analysis and statistical thinking in the information age, mathematics curriculum standards in the U.S. have recently increased expectations for student learning in the domain of statistics and probability. More than 180 teachers in 36 public school districts in Florida applied for a two-week summer institute designed to increase teachers’ content and pedagogical content knowledge in statistics and probability. Individual teachers were assigned at random to a treatment or business-as-usual comparison group. The two-week institute increased teachers’ knowledge of statistics. Data analyses identified an interaction between years of teaching experience and treatment, indicating that the teachers with more than 10 years of experience had larger knowledge gains than their less-experienced peers. These results underscore the need for professional development for teachers so that they may implement policies emphasizing this branch of the mathematical sciences in the secondary mathematics curriculum. Given the observed lower baseline knowledge scores for teachers with more years of teaching experience, we posit these implications are particularly applicable to teachers who completed their own formal education more than 10 years ago.