Rule Reference

R021 — Hidden Sheet Dependency

R021 (Hidden Sheet Dependency) flags a hidden or very-hidden worksheet that is referenced by at least one formula on a visible worksheet. Reviewers examining a workbook through normal navigation cannot see a hidden sheet's contents, so errors, stale values, or edits made to a hidden sheet propagate silently into visible outputs without appearing anywhere a standard review would look. Hidden sheets referenced only by other hidden sheets, or not referenced by any visible sheet at all, are not flagged.

R022 — Merged Cells in Data Region

R022 (Merged Cells in Data Region) is the sole rule in the Structural Hygiene taxonomy category. It flags a merged cell range whose bounding box overlaps the formula-bearing region of the same worksheet. Merged ranges confined to header rows at the top of a sheet are excluded, since merging header cells for presentation is a common, low-risk practice distinct from merging cells inside the calculation region itself.

R023 — Aggregation Range Gap

R023 (Aggregation Range Gap) flags a formula cell that sits immediately adjacent to an aggregation formula's range — one row above or below a SUM, SUMPRODUCT, or SUBTOTAL range — but is not itself included in that range. The adjacent cell may represent a line item that was silently excluded from the total. R023 is the sole member of its own taxonomy category (Aggregation Logic) and, despite the category's narrow scope, is critical severity and one of five critical-override rules under the SM-2.0 scoring methodology.

R024 — Unused Input Driver

R024 (Unused Input Driver) flags a numeric, non-formula cell on a worksheet already identified as a model's input layer that no formula anywhere in the model actually references. An input that cannot be traced to any output is either a stale assumption that was never connected, or a driver that was intended to feed a calculation but was silently missed. Confidence is deliberately kept low, since the engine only resolves single-cell references and cannot see a driver consumed only through a range formula or an Excel data table.

R025 — Orphaned or Invalid Named Range

R025 (Orphaned or Invalid Named Range) checks every defined name in the workbook against two independent conditions. An invalid name points to a broken or unresolvable target, typically because the range or sheet it once pointed to was deleted. An orphaned name is valid and resolvable but is not referenced by any formula anywhere in the model, meaning the value it represents has no path to any output. Each condition produces its own finding, at different confidence levels, reflecting how directly observable each defect is.

R026 — Missing Input Validation

R026 (Missing Input Validation) checks numeric, non-formula cells on a model's identified input sheets for Excel data validation coverage. An uncovered cell allows any value to be typed in, including one outside a sensible or intended range, with no in-model mechanism to catch the error at entry. When most of a sheet's input cells lack validation, R026 reports one sheet-level summary finding rather than flagging every cell individually.