The reliability of the TPACK scale developed by Schmidt et al. (2009) and related adaptations: a Reliability Generalization Meta-Analysis (REGEMA)

This study aims to synthesize the internal consistency reliability coefficients (Cronbach’s α) reported in the literature for the TPACK scale developed by Schmidt et al. [1] using the Reliability Generalization Meta-Analysis (REGEMA) approach. We conducted a systematic search in the Web of Science (WoS) and Scopus databases covering 2010 to 2025, initially yielding 604 records. An audit of the original XLS coding file and JASP dataset identified one duplicate study record and one study represented by two repeated (pre/post) reliability coefficients. The qualitative synthesis therefore comprised 69 unique studies. The quantitative synthesis included 48 effect estimates from 47 studies; 22 unique studies did not contribute a poolable effect estimate (21 lacked a sample-specific α and one reported α but not the item count required for its sampling variance). Because one study contributed two dependent coefficients, the primary Bonett-transformed analysis was estimated as a multilevel random-effects model with effect estimates nested within study. The primary model produced a pooled Cronbach’s α of 0.944 (95% CI [0.933, 0.953]; 95% PI [0.812, 0.983]). A multilevel untransformed-alpha sensitivity model yielded α = 0.934 (95% CI [0.921, 0.948]; 95% PI [0.845, 1.024]); its prediction interval again exceeded the theoretical maximum of a reliability coefficient, supporting use of the transformed model. Study-level heterogeneity remained substantial (τ² = 0.376 on the Bonett-transformed scale). Influence diagnostics identified Cao et al. [2] ( n = 440, 23 items, α = 0.708) as the most influential low-reliability observation. Overall, the findings indicate high internal consistency for the TPACK scale and closely related adaptations across the studies included in this synthesis. Four of the 48 pooled coefficients came from closely related but non-identical TPACK instruments; sensitivity analysis excluding these effects did not materially change the pooled estimate. The results also highlight the importance of reporting sample-specific reliability estimates in future TPACK research.