SOURCE SNAPSHOT
Start with provenance before arithmetic.
INPUT AND EVIDENCE LEDGER
Classify every field before using it.
| Field | Value | Origin |
|---|---|---|
| Reported prices | ₩780M, ₩800M, ₩820M, ₩830M, ₩840M, ₩1,200M | Controlled test fixture |
| Cancelled record | ₩1,200M | Official 해제 status applied |
| Comparable filter | Same complex and area bucket | APT rule under test |
| Statistic | Median | Robust baseline choice |
REPRODUCIBLE WORK
Run the quality-control chain.
| Check | Formula or rule | Result |
|---|---|---|
| Unfiltered median | Average of third and fourth values | ₩825M |
| Apply status | Exclude the record marked 해제 | Five active records remain |
| Active median | Middle of five active values | ₩820M |
| Audit finding | ₩825M − ₩820M | ₩5M upward bias in this fixture |
DECISION READING
The audit finding.
The bias is small in this fixture but can be material in thin markets. The status filter must happen before summaries, highs, recovery ratios, or rankings are calculated.
OWNER AUTHORIZATION + VERIFICATION RECORD
One accountable operator and a reproducible check record.
The TOOOLBOX site owner authorized this publication scope and remains the correction contact. The checks below were completed during preparation with AI-assisted implementation; they are an audit record, not a claim of licensed professional review.
- Review ID
- TB-APT-13-20260902
- Owner role
- TOOOLBOX site owner and developer
- Release scope
- Owner-authorized · 2026-09-02
- Correction channel
- Public contact page
- Confirmed the disclosure system's cancellation legend.
- Ran the fixture with and without the cancelled record.
- Checked that no fixture price is described as a live market transaction.
BOUNDARIES
What passed data checks still cannot prove.
- The six prices are a transparent test fixture, not claims about a named apartment.
- Cancellation status does not explain why the transaction was cancelled.
- Other revisions and matching errors require separate checks.
SENSITIVITY
Failure modes to retest.
- The effect grows when the sample is smaller or the cancelled price is more extreme.
- Mean prices are usually more sensitive to an outlier than medians.
- Late cancellation reports require the stored baseline to be recomputed.
MORE APT DECISION NOTES
Compare another evidence pattern.
The related notes deliberately use different questions, data states, and editorial forms.