NCPA - National Center for Policy Analysis

Linking Teacher Skills to Student Achievement

December 10, 2014

International assessment tests have shown large gaps in students' cognitive skills across countries. In a new paper published by the National Bureau of Economic Research, Eric Hanushek of the Hoover Institution and Marc Piopiunik and Simon Wiederhold of the Institute for Economic Research ask whether teachers' cognitive skills might explain the gap: is there a link between teacher quality and student performance?

Previous research has focused on the academic achievements of teachers. For example, 100 percent of teachers in Singapore, Finland and South Korea come from the top third of their countries' academic achievers, while just 23 percent of American teachers come from the top third.

Using data from the Programme for the International Assessment of Adult Competencies (PIAAC), which measures cognitive skills of adults in OECD countries, Hanushek, Piopiunik and Widerhold note that the literacy skills of teachers in Italy and Russia (the countries with the lowest-performing teachers) are similar to the skills of employed Canadians with only vocational degrees, while the literacy skills of teachers in Japan and Finland (the countries whose teachers demonstrated the best cognitive skills) are higher than the cognitive skills of Canadians with master's degrees or PhDs.

According to the report from Hanushek, Piopiunik and Widerhold, teachers' cognitive skills do have a significant relationship to student achievement:

  • Students in countries that score well on international achievement tests have teachers with higher numeracy and literacy skills.
  • Finland has the most skilled teachers according to PIAAC. Were all countries to bring its teachers to the level of Finnish teachers, student performance would improve. The United States would see an increase in math performance of 54 percent of a standard deviation, while Russia would see math improvement of 73 percent of a standard deviation.

The authors also report that teachers' wages are related to teachers' cognitive skills; an increase in teacher salaries by one standard deviation is associated with an increase in teacher math skills of 40 percent of a standard deviation and an increase in literacy skills of 30 percent of a standard deviation.

The authors conclude, "Smarter teachers produce smarter students."

Source: Eric A. Hanushek, Marc Piopiunik and Simon Wiederhold, "The Value of Smarter Teachers: International Evidence on Teacher Cognitive Skills and Student Performance," National Bureau of Economic Research, Working Paper No. 20727, December 2014. 


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