Measuring Teacher Effectiveness Across Time: What Does TIMSS Reveal About Education System Level Trends?

Abstract

To understand whether there are identifiable trends in teacher quality and instructional metrics over time, it is important to first recognize that measures of teacher effectiveness may vary by education system. Descriptive results for the teacher quality measures related to mathematics drawn from twenty years of the IEA’s Trends in International Mathematics and Science Study (TIMSS) data provide a general picture of the variation in such measures; additional consideration is given to student-level variables. Combining information from multiple cycles of TIMSS, with a specific emphasis on teacher variables, greater focus is given to the post-2003 TIMSS data, largely because these later cycles contain additional teacher-related measures (such as preparedness to teach mathematics topics). Changes in education system means may be due to changes in underlying teacher characteristics. The data suggests that, among the pool of countries that participated in all the TIMSS between 2003 and 2015, there have been increases in the international averages for the number of years of experience that teachers possess, their level of educational qualification to teach mathematics, and classroom time spent on mathematics instruction. However, instructional alignment with national standards has remained surprisingly modest (at around 55–60%) and the international average for instructional alignment declined for grade eight over twenty years of TIMSS. The results suggest that, in many countries, teachers (especially grade four teachers) retain a substantial degree of discretion in what to teach. Variability in teacher behaviors related to opportunity to learn suggests it is highly advisable to consider this factor in studies of teacher effectiveness.