> ## Documentation Index
> Fetch the complete documentation index at: https://mehen.ophi.dev/llms.txt
> Use this file to discover all available pages before exploring further.

# Section Balance

> Whether a Markdown document is chunked in a maintainable way.

**Section Balance** checks whether the document is chunked in a maintainable way. It penalizes:

* Oversized sections at the 95th percentile.
* A high rate of very large sections.
* A high rate of tiny sections.
* Heading skips (e.g., `H2 → H4`).
* Heading depth deviation from a profile-specific expectation.

## Inputs

* The [section tree](/metrics/markdown/section-tree).
* Per-section word counts from the LOC family.
* Profile-specific expected depth (default depends on doc type).

## How DMI uses it

Section Balance feeds [DMI](/metrics/markdown/dmi) via the `S_norm` term — "poor section balance"
*reduces* DMI.

## References

* Miller, G. A. (1956). *The magical number seven, plus or minus two: some limits on our capacity
  for processing information.* Psychological Review 63(2): 81–97 — working-memory ceiling that
  motivates the oversized-section penalty.
  [DOI](https://doi.org/10.1037/h0043158).
* Sweller, J. (1988). *Cognitive load during problem solving: Effects on learning.* Cognitive
  Science 12(2): 257–285 — cognitive-load theory underlying the "too-many-tiny-sections vs.
  too-large-section" trade-off.
  [DOI](https://doi.org/10.1207/s15516709cog1202_4).

## See also

* [Section tree](/metrics/markdown/section-tree) — input structure.
* [Filler / Lazy Risk](/metrics/markdown/filler-lazy-risk) — separate "lazy sectioning" sub-score.
* [Good Scaffold](/metrics/markdown/good-scaffold) — orthogonal "did the scaffolding help?" axis.