## TL;DR
Pull the actual standard deviation from the validation result before adjusting the range: compute the column stdev in the warehouse for the same batch, and check whether a unit change, a new segment of rows, or a genuinely wider spread moved it. expect_column_stdev_to_be_between compares the batch stdev against fixed bounds, so any population change moves the statistic even when every individual value is valid.

```text
great expectations error: expect_column_stdev_to_be_between failed standard deviation out of range
```

## Use this when
- The check or run fails with this symptom: expect_column_stdev_to_be_between fails with the standard deviation out of range.
- You are working on a Great Expectations suite that guards a numeric column spread and the failure repeats on the same data or configuration.
- You need the failing rows, rule, or stage isolated before changing thresholds or code.

## Not for this skill when
- A column whose spread is expected to grow with a planned population change, where the bounds need a reviewed update rather than a data fix.
- The error text names a different tool, stage, or root cause. Match the verbatim error first and use that skill.

## Steps
1. Read the observed value in the validation result and compare it with the configured min and max. Verify: the distance outside the range is known
2. Compute the stdev for the same column over the previous good batches. Verify: the batch where the spread changed is identified
3. Break the failing batch down by the main segment columns and compute stdev per segment. Verify: one segment with a different spread is found or ruled out
4. Fix the cause: correct a unit or scale change at the source, exclude a wrongly included segment in the batch definition, or widen the bounds with a reviewed change. Verify: the expectation passes on a rerun of the same batch
5. Rerun the full checkpoint. Verify: no other expectation on the column regresses

## Variant phrasings
### expect_column_stdev_to_be_between failed out of range
The shorter phrasing focused on the named failure.
### great expectations standard deviation expectation failed
The symptom phrasing a searcher tries next.
### column stdev out of range great expectations fix
The variant naming the failing stage or tool directly.

Compatibility: Great Expectations 0.18 and 1.x with expect_column_stdev_to_be_between

## Why it happens
Standard deviation is a population statistic. Adding a new customer segment, switching a column from dollars to cents, or including test rows widens the spread, and the fixed bounds from an older population no longer describe the data.

## Edge cases / pitfalls
- Stdev is sensitive to a handful of extreme values; check the max and a percentile before concluding the whole distribution moved.
- An empty or tiny batch produces a meaningless stdev; confirm the batch row count before debating the bounds.

## Provenance

Resolved from the public thread: https://vectle.com/posts/pst_16-SPxKOQVDwcwjvaz5u9Q