Asking price or completed sale? Build a reliable property comparison
Separate asking prices from completed transactions when comparing overseas property. Record source dates, unit differences, incentives and the limits of incomplete sales evidence.
A screenshot is evidence of an offer, not a sale
Three similar listings at a high price may all belong to the same seller, include expired offers or describe units that remain unsold. They can help identify alternatives available to a buyer. They do not, without further evidence, establish achieved transaction values or justify a forecast that a new purchase will sell at the same level.
RICS guidance on comparable evidence addresses the quality and analysis of evidence used in valuation. A broker's shortlist is not automatically a professional valuation. Use the discipline of recording evidence without claiming the authority of a valuation instruction that has not been undertaken.
Classify the source before calculating an average
For each comparable, record the source, capture date and price status. Distinguish a public listing, a developer quote, a reported reservation and a completed transaction supported by appropriate evidence. Ask whether the price includes furniture, fees, a rental incentive or another concession. Respect confidentiality and legal access limits when requesting transaction records.
If a seller says a neighbour achieved a particular price, record it as an unverified report until supported. Do not upgrade it to a completed-sale fact because it appears in several presentations. Repeated copies of the same claim are not independent evidence.
Compare the right characteristics
| Dimension | What to record | Why a simple average can mislead |
|---|---|---|
| Rights and term | The documented interest being offered | Different rights are not interchangeable |
| Size | Area and measurement basis | Balcony-heavy and internal areas can differ |
| Timing | Evidence date and completion stage | An early launch and a completed home have different conditions |
| Unit | Floor, outlook, layout and condition | Similar project names do not make units identical |
| Price package | Included items, charges and incentives | Headline price may hide a different total cost |
Avoid assigning an invented adjustment percentage to every difference. If a material difference cannot be assessed credibly, show it as a limitation or choose a better comparable.
Use a worked comparison without pretending it is a valuation
Suppose an illustrative shortlist contains a 5.0 million THB asking price, a 4.8 million THB reported reservation and a 4.7 million THB documented completion. The three figures have different evidence status. Their numerical average is approximately 4.83 million THB, but that average is not a defensible sale-price estimate simply because the arithmetic is correct.
Check whether the units have comparable rights, area, condition and dates. If the completed unit required renovation or included a different area, explain that difference. Present a range only when the supporting evidence justifies it; do not imply precision by adding decimal places to weak inputs.
Turn the comparison into useful buyer questions
Ask what alternatives the buyer could actually purchase now, what evidence supports an exit assumption and which material facts remain unknown. A buyer seeking personal use may reasonably prefer a more expensive unit that meets an essential requirement. A buyer focused on resale needs a more demanding discussion of the evidence behind the future buyer and price.
For a referring agent, keep the evidence sheet with the buyer brief. The local team can then investigate a specific gap rather than receiving a request to “prove the project is below market”. An independent qualified valuer may be appropriate when a formal opinion of value is needed.
Questions buyers and agents ask
Are public listings useless?
No. They show available competition and seller expectations, provided their status and date are clear.
Can I call a reservation a completed transaction?
No. Record the event actually evidenced. Reservation, contract, transfer and payout are distinct stages.
Does the lowest comparison price establish fair value?
No. It may concern a materially different unit, rights package or condition. Investigate the difference before drawing a conclusion.
Sources and scope
RICS: Comparable evidence in real estate valuation. Examples are invented for explanation. This article is not a valuation, price forecast or investment recommendation.
Educational material. Examples are illustrative; legal, technical, tax and investment decisions need case-specific professional advice.
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