A growth mindset is the belief that intellectual abilities are not fixed, but can be developed. Do students who are taught a growth mindset earn higher grades and test scores?

Brooke Macnamara and her colleagues, who conducted a meta-analysis of growth mindset interventions, found that when students were taught a growth mindset, they showed significantly higher achievement. But Macnamara believes that the effects of these programs or interventions, while statistically significant, are too small to be practically meaningful.

My colleagues and I, along with educational evaluation experts, economists and the World Bank, disagree.

You’re probably thinking that of course I would say the effects of growth mindset intervention are meaningful since my research is what led to their creation.

Yet our disagreement with Macnamara rests on exactly what one considers to be a meaningful effect size for an educational intervention. An effect size is a way to standardize treatment benefits across very different outcomes, like test scores and grade point averages.

Macnamara states that the average or typical effect size for an educational intervention is .57. In the case of grade point averages, this would mean that students in a typical intervention group would have grades that are about .57 points higher than a control group on a 4.0 scale.

Effects on grades

Looking closely at this literature, however, we found that most of the studies that yielded this .57 effect size did not examine effects on actual grades and standardized test scores at all. They often looked at performance on a quiz given minutes after students were taught something.

The right comparisons for the growth mindset interventions are educational interventions that looked at effects on actual grades and major test scores. As the examples below show, an effect size of .20 for grades or test scores within a school year is about the best you can expect. This is true of even the most costly and comprehensive programs – and especially for adolescents, the age group for which most growth mindset interventions take place.

For example, smaller class sizes for all the elementary schools in a state had an effect size of .20. In fact, a whole year of school learning from grade 9 to grade 10 yields an effect size of about .20 across subjects, as measured by standardized tests. A whole year with a good teacher, as opposed to an average teacher, usually yields an effect size of about .20.

Based on a search of the What Works Clearinghouse, a government site that reviews high-quality research on educational interventions, there are almost no rigorously evaluated interventions with significant effects on high school students’ achievement. One of the most highly regarded of the few successful programs for high school students is a literacy program for at-risk 9th grade readers, with an effect size of .06 and a cost of almost US$2,000 per student.

Sue Dynarski, a leading educational economist, says that in real-world settings, an effect size of .20 is “a large effect.”

The effect size that Macnamara reports for growth mindset interventions is .19 for students at risk for low achievement – that is, for the students most in need of an academic boost. When you include students who are not at risk or are already high achievers, the effect size is .08 overall. These effects don’t look so small when you use the right comparisons. But there’s more.

Inexpensive and efficient

Many growth mindset interventions last about an hour and cost less than $1 per student. They are delivered directly to students and do not change anything about the teacher, classroom or school. And yet they provide a reasonable chunk of the effects delivered by more extensive and costly interventions, even many of the best-in-class school reforms – such as smaller classes or better teachers.

Direct-to-student interventions are just one way to address students’ mindsets. Colleagues at the University of Washington and Indiana University are now building a curriculum to help teachers implement growth mindset practices in their classrooms. This will take us closer to understanding the true potential of growth mindsets to enhance students’ learning.

Our interventions for students are available to educators at no cost. The teacher curriculum, when fully developed and fully tested, will be as well. It should be noted that I have no financial relationship with any entity that sells mindset-related products.

Approaches to cultivating a growth mindset are in their infancy. Much remains to be learned. In pursuit of this knowledge, my colleagues and I have just completed a nationwide study of mindset interventions, examining where they work best and how they can be made better. We believe the most exciting part of our scientific journey is just beginning.