Average Is Overrated: Variability Within and Between Countries on PISA

• In Event: Friday Roundtable Session 9:45 am
  In Roundtable Session: Innovation in Statistical Methods (Table 31)

Abstract

The PISA test is a key indicator of the health of worldwide education systems; high average performance typically indicates success. The current study reconceptualizes success as both high average performance and small within-country variability after controlling for GDP—which countries do the most with what they’ve got by serving all students well. Using a mixed effects location scale model, the relationship between GDP and: (1) mean performance, (2) variability between, and (3) variability within 65 countries is examined using the PISA 2012 mathematics scores of 480,174 students. The covariance between variability in means and variability in within-country performance is also estimated to determine if there is a relationship between average performance and homogeneity in PISA scores.

Author

• Megan E. Welsh, University of California - Davis