Psychologist Carol Dweck created the 3-item Growth Mindset Scale to measure how much people believe that they can get smarter if they work at it. The scale is freely available.
Access and Use
Aronson, J., Fried, C. B., & Good, C. (2002). Reducing the effects of stereotype threat on African American college students by shaping theories of intelligence. Journal of Experimental Social Psychology, 38, 113-125. https://doi.org/10.1006/jesp.2001.1491
Card, D. (2001). Estimating the return to schooling: Progress on some persistent econometric problems. Econometrica, 69(5), 1127-1160. https://doi.org/10.1111/1468-0262.00237
Claro, S., Paunesku, D., & Dweck, C. S. (2016). Growth mindset tempers the effects of poverty on academic achievement. Proceedings of the National Academy of Sciences, 113(31), 8664-8668. https://doi.org/10.1073/pnas.1608207113
Haimovitz, K., & Dweck, C. S. (2016). Parents’ views of failure predict children’s fixed and growth intelligence mind-sets. Psychological Science, 27(6), 859-869. https://doi.org/10.1177/0956797616639727