Structural Limits of Evidence Aggregation Under Heterogeneous Observational Interfaces: A Minimal Diagnostic Toy Model

This technical note presents a minimal diagnostic toy model illustrating how global statistical significance can emerge when evidence from heterogeneous observational interfaces is aggregated using classical methods such as Fisher and Stouffer combinations. The example shows that locally valid studies may generate a statistically significant global result even when the underlying observational interfaces are structurally different. The purpose of the note is not to introduce new statistical methodology but to highlight an implicit structural condition of evidence aggregation: global evidential metrics are meaningful only when the contributing observations belong to sufficiently comparable inferential interfaces. The model is intentionally minimal and purely diagnostic.