Pygmalion effects in the classroom: Teacher expectancy effects on students' math achievement

• Longitudinal study of teacher expectancies in math classes.
• Large sample of 73 teachers and their fifth-grade students (N = 1289).
• Teacher expectancies predict students' achievement for two outcome measures.
• Teachers' effect on achievement was partly mediated by students' self-concept.
• No teacher effect on between-students' level when controlling for prior achievement.

According to the Pygmalion effect, teachers' expectancies affect students' academic progress. Many empirical studies have supported the predictions of the Pygmalion effect, but the effect sizes have tended to be small to moderate. Furthermore, almost all existing studies have examined teacher expectancy effects on students' achievement at the student level only (does a specific student improve?) rather than at the classroom level (do classes improve when teachers have generally high expectations of their students?). The present study scrutinized the Pygmalion effect in a longitudinal study by using a large sample in regular classrooms and by differentiating between two achievement outcomes (grades and an achievement test) and two levels of analyses (the individual and classroom levels). Furthermore, students' self-concept was studied as a possible mediator of the teacher expectancy effect on achievement. Data come from a study with 73 teachers and their 1289 fifth-grade students. Multilevel regression analyses yielded three main results. First, Pygmalion effects were found at the individual level for both achievement outcomes. Second, multilevel mediation analyses showed that teacher expectancy effects were partly mediated by students' self-concept. Third, teachers' average expectancy effects at the class level were found to be nonsignificant when students' prior achievement was controlled.