This concept note introduces the distinction between procedural operativity and substantive reviewability within ongoing work on criteriology and the Self-Matryoshka Analytical Framework (S-MAF). Procedural operativity concerns the functioning of procedural mechanisms, while substantive reviewability concerns the extent to which the documentary, factual, evaluative, classificatory, or competence-related conditions underlying decisions and processes can be examined or reconstructed. The note proposes this distinction as an analytical tool for examining situations in which procedural functioning and reviewability do not necessarily coincide. An analytical matrix is included to illustrate four possible configurations formed by variations in procedural operativity and substantive reviewability. The concepts are intended to support further work on reviewability, reconstructability, identifiability, analytical visibility, documentary shielding, and related analytical phenomena.