Cronbach's Alphas of knowledge tests vary widely, with a 90% prediction interval of [0.35, 0.96]¶

Claim · All claims
Evidence · 1 study · quant-synthesis r2 · q3
Currency · newest study 2025 · not yet checked against its sources · not reviewed by a person · recheck by 2028: tool and model accuracy changes quickly

Subclaims¶

q3 i? The 90% prediction interval for knowledge test Alphas spans [0.35, 0.96], with between-studies variance τ² = 0.73 and I² = 98.68%. → Peter A. Edelsbrunner 2025

Evidence¶

Peter A. Edelsbrunner 2025¶

Peter A. Edelsbrunner, Bianca A. Simonsmeier, Michael Schneider. (2025). The Cronbach’s Alpha of Domain‑Specific Knowledge Tests Before and After Learning: A Meta‑Analysis of Published Studies. Educational Psychology Review. https://doi.org/10.1007/s10648-024-09982-y

q3 · i? · quant-synthesis · r2

Between-studies heterogeneity was very large: τ² = 0.73, I² = 98.68%. The authors state this "makes it difficult to predict the Alpha for future studies" and suggest the PI range as a guideline for tests with 20 items.

"The 90% PI for the overall Alpha was [0.35, 0.96]. There was an estimated between-studies variance of τ2 = 0.73, which made up for an estimated proportion of I2 = 98.68% of the total variability."

Discussion¶

Related Claims¶

• Alpha of knowledge tests is higher for language and mathematics than for science and social sciences/humanities — related
• Meta-analytic average Cronbach's Alpha of domain-specific knowledge tests is 0.85 with expected item intercorrelation of 0.22 — related
• Open response format is associated with higher Alpha than multiple choice in knowledge tests — related
• Alpha of knowledge tests increases after interventions from pretest to posttest — related
• Alpha is negatively related to sample mean age, and knowledge type shows no effect after controlling for test length — related
• Alpha of knowledge tests is substantially related to the number of items in the test — related