Just to piggyback off of this comment, from anecdotal experience as a high school teacher, I found the portion of the replication quoted in Margin Revolution to be quite true:
"… as expected, average effects were small because many students are already doing well, do not have motivational issues, or are not in environments that encourage or support growth-mindset behaviors. When we take account of such factors, more noteworthy effects emerge. The improvements in the gateway outcome of 9th grade GPA were concentrated among adolescents who are at significant risk for compromised well-being and economic welfare: those with lower levels of prior achievement attending relatively lower achieving schools. The finding that an intervention can redirect this adolescent outcome in this sub-group, in under an hour, without training of teachers, and at scale (i.e. in a random sample of nation’s schools), represents a significant advance."
Personal experience lines up with the result that lower-achieving students may benefit more from the "growth mindset" idea than others. For instance, I did notice that messaging I gave to students with a "fixed mindset" towards studying CS/math seemed to improve motivation, work ethic and interest over the course of a semester.
"… as expected, average effects were small because many students are already doing well, do not have motivational issues, or are not in environments that encourage or support growth-mindset behaviors. When we take account of such factors, more noteworthy effects emerge. The improvements in the gateway outcome of 9th grade GPA were concentrated among adolescents who are at significant risk for compromised well-being and economic welfare: those with lower levels of prior achievement attending relatively lower achieving schools. The finding that an intervention can redirect this adolescent outcome in this sub-group, in under an hour, without training of teachers, and at scale (i.e. in a random sample of nation’s schools), represents a significant advance."
Personal experience lines up with the result that lower-achieving students may benefit more from the "growth mindset" idea than others. For instance, I did notice that messaging I gave to students with a "fixed mindset" towards studying CS/math seemed to improve motivation, work ethic and interest over the course of a semester.