ReplicationScope: Experimental replicability, effect-size heterogeneity and meta-analytic uncertainty

01 · Context

Research question

How much variation in each replicated psychological effect is attributable to laboratory differences rather than sampling error?

02 · Methods

Approach

• Audit effect direction, estimates, variance semantics and laboratory labels.
• Keep independent psychological contrasts separate instead of pooling them indiscriminately.
• Use Fisher-z transforms and restricted maximum-likelihood random-effects models.
• Inspect tau², I², prediction intervals, influence and leave-one-laboratory-out stability.

03 · Evaluation

Reported results

• An R 4.5.0 execution loaded 1,593 rows from the Many Labs 2 processed effect-summary table, with 1,474 non-missing r/variance pairs, and fitted preliminary REML meta-analyses for 26 eligible laboratory contrasts.
• The observed execution artifacts, input hashes, package versions and restrictions are documented in the research evidence ledger. Full reproducibility and sensitivity gates are still outstanding.
• Interpretation remains exploratory and no causal, diagnostic or peer-reviewed conclusion is asserted.
• Five highest-I² contrasts were refitted after ten selected laboratory deletions each (50 sensitivity refits total). The check is limited to these chosen exclusions and does not replace a full effect-coding and influence audit.