APT · EVIDENCE TIMELINE · NOTE 14

Normalize area before comparing two sale records

A transaction-field audit shows why raw prices for 59.9㎡ and 84.9㎡ homes cannot be ranked without an area-normalized view.

REPRODUCIBLE WORK

Follow the evidence in the order it becomes usable.

01

Read source fields

Transaction amount + exclusive-use area

Two differently sized homes
02

Normalize A

₩720M ÷ 59.9㎡

About ₩12.02M/㎡
03

Normalize B

₩930M ÷ 84.9㎡

About ₩10.95M/㎡
04

Interpret

A normalized rate − B normalized rate

A is about 9.8% higher per ㎡ despite the lower total price

SOURCE SNAPSHOT

Anchor the event to a source and time.

INPUT AND EVIDENCE LEDGER

Keep the snapshot attached to its origin.

FieldValueOrigin
Record A₩720M / 59.9㎡Controlled fixture using official fields
Record B₩930M / 84.9㎡Controlled fixture using official fields
Area fieldExclusive-use areaMOLIT transaction schema
ComparisonWon per exclusive-use ㎡APT transformation

DECISION READING

What survives the timeline check.

Total price answers an affordability question; price per square metre answers a different comparability question. APT should show both and still avoid treating units with different floor, orientation, condition, or date as identical.

SENSITIVITY

Where the chain can go stale.

  • Using gross floor area instead of exclusive-use area would change the denominator.
  • Renovation, floor, view, and transaction month can dominate the normalized difference.
  • Narrower area buckets improve comparability but reduce sample size.

BOUNDARIES

Do not extend the timestamp into a promise.

  • The pair is a calculation fixture, not a named-property valuation.
  • Per-square-metre normalization does not make two units fully comparable.
  • Only reported transactions, not listings, belong in this evidence layer.

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-14-20260902
Owner role
TOOOLBOX site owner and developer
Release scope
Owner-authorized · 2026-09-02
Correction channel
Public contact page
  1. Verified the official interface exposes price and exclusive-area fields.
  2. Recomputed both normalized values and the percentage difference.
  3. Added non-area comparability limits before publication.

MORE APT DECISION NOTES

Compare another evidence pattern.

The related notes deliberately use different questions, data states, and editorial forms.

12 · Use the official rate range as a stress band13 · A cancelled transaction must leave the price baseline