R022 — Merged Cells in Data Region
Executive Summary
Key Takeaways
- ✓ R022 is the sole rule in the Structural Hygiene taxonomy category — it has no sibling rules by category.
- ✓ It flags a merged cell range that overlaps a worksheet's formula-bearing data region, not merged cells confined to header rows above the data.
- ✓ Merged cells in a data region break formula references when rows or columns are later inserted, a structural fragility rather than a calculation error in the current state of the model.
- ✓ Hidden worksheets are excluded from this check, since R021 already addresses hidden-sheet risk separately.
Purpose¶
R022 detects a merged cell range that overlaps a worksheet's formula-bearing data region. It is the sole rule in the Structural Hygiene taxonomy category, addressing a formatting-level structural risk distinct from a calculation error in the model's current state.
Detection Logic¶
For each worksheet, the bounding box of its formula-bearing cells is computed, along with the row of the first formula cell, which establishes an adaptive boundary between header rows and the data region proper. Every merged range on the sheet is then checked: a range confined entirely above that first-formula-row boundary is excluded as a header merge, and a range overlapping the formula-bearing bounding box is flagged. Hidden and very-hidden worksheets are excluded from this check entirely, since hidden-sheet risk is addressed separately by R021 (Hidden Sheet Dependency).
Why It Matters¶
A merged cell range sitting inside a worksheet's calculation region does not itself produce an incorrect result in the model's current state — the risk is structural fragility going forward. Inserting a new row or column near a merged range can behave unpredictably in Excel, and formulas that reference cells inside or adjacent to a merged range can shift or break in ways that a formula referencing ordinary, unmerged cells would not. This is a hygiene concern about how safely the model can be extended or edited later, not a claim that the merged cells are currently producing a wrong number.
Evidence Produced¶
A triggered R022 finding's evidence identifies the specific sheet and the merged range's cell address span, together with a description noting that the range overlaps the sheet's formula-bearing data region and that merged cells can break formula references when rows or columns are inserted.
Severity¶
High. Weight 7.0. R022 is not one of the five critical-override rules. Confidence is always high, since a merged range's location relative to the formula-bearing region is a directly observable fact.
Example¶
Trigger. A worksheet's data region runs from row 5 to row 40 across several columns, and a merged
range spans B18:C18 — inside that data region. R022 flags this merged range.
Non-trigger. A merged range spans A1:F1, a title header confined entirely to row 1, above the
worksheet's first formula row. R022 does not fire, since the merge is confined to the header region.
Recommended Remediation¶
Unmerge all cells within the worksheet's formula-bearing data region, restructuring any presentation formatting that relied on the merge (such as a section label) to use a different technique — for example, a label in a single cell with formatting applied across the row, rather than a merged cell spanning it.
Related Rules¶
R022 is the sole member of the Structural Hygiene taxonomy category — it has no sibling rules by category. See the Rule Taxonomy page for the full classification, and the Rule Reference for every published rule page.
Related Articles¶
No existing Knowledge Centre technical guide addresses merged-cell structural risk specifically as of this writing; this section will be updated with a link in the same edit that publishes one.
Version History¶
No version-specific changes to R022's severity, weight, or category are recorded as of engine version 2.1.0. This section will be updated in the same edit as any future change to the rule's declared attributes.
How OXXON tests thisRun a free structural check with FMAE
Frequently Asked Questions
What does FMAE rule R022 check for?
A merged cell range whose bounding box overlaps the formula-bearing data region of the same worksheet — as distinct from a merged range confined entirely to the header rows above the data, which is excluded.
Why are merged cells in header rows excluded?
Merging cells at the top of a worksheet for a title or section header is a common, low-risk presentation practice, distinct from merging cells inside the region where formulas and data actually live. R022 targets the latter specifically.
Is R022 the only rule in its taxonomy category?
Yes. Structural Hygiene is one of the six FMAE rule categories, and R022 is its sole member — it has no sibling rules to cross-reference within its own category.
Why does R022 skip hidden worksheets?
Because hidden-sheet risk is already addressed separately by R021 (Hidden Sheet Dependency); R022 focuses specifically on the structural hygiene risk of merged cells within a visible sheet's data region.
Related Articles
FMAE Rule Taxonomy
Every rule in the FMAE structural rule pack declares a category attribute at the point it is defined in source — this is not a classification imposed on the rules afterward for documentation purposes, it is the classification the engine itself uses. Six categories cover all 26 rules — Structural (18 rules), Assumptions Governance (1), Integrity Controls (2), Structural Hygiene (1), Aggregation Logic (1), and Model Governance (3). This page publishes that taxonomy as the FMAE equivalent of a control catalog's classification scheme, cross-linked to the Rule Reference page for each member rule.
Finding Data Model & Confidence
Every FMAE finding carries the same fixed structure — which rule triggered it and that rule's identity at the time it ran, its evidence, a narrative explanation, and a confidence label of high, medium, or low. Confidence is a deterministic categorical label derived from how strongly a row's cells agree on a pattern, not a machine-learning probability estimate. Stating this plainly matters, since describing FMAE's confidence as AI-derived or probabilistic would overstate what the engine actually does.