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Appraisers find comparable sales through listing databases, recorded transfers, assessor records, transaction participants, and other reliable property sources. Finding an address and a sale price is only the beginning. The appraiser must understand what actually sold, the property’s condition at that time, and whether the transaction provides useful evidence for the home being valued.
For a homeowner, the important question is not simply “Which website has the comps?” It is “How were the facts checked, and why do these transactions help explain my property’s value?” This guide follows that evidence trail. The separate guide to how appraisers choose comparable sales explains how the strongest candidates are selected.
Where comparable-sale information comes from
No single source answers every question about a transaction. A listing may contain extensive photographs but an incorrect area figure. A deed can establish a recorded transfer without explaining the home’s interior condition. An assessor’s property card can help identify a parcel while omitting a recent improvement. Good research uses the strengths of each source and recognizes its limitations.
| Source | Useful evidence | Question still to resolve |
|---|---|---|
| Multiple listing service (MLS) | Listing history, photographs, descriptions, marketing dates, reported terms | Was the information accurate, and did the condition change? |
| Deed and land records | Recorded ownership transfers and property identification | Was this an open-market sale of the same property interest? |
| Assessor records | Parcel characteristics, building information, assessment history | When was the record updated, and how was area classified? |
| Transaction participants | Sale circumstances, concessions, repairs, occupancy or unusual terms | Can important statements be checked against other evidence? |
| Maps, photographs and observation | Location, access, surroundings and visible features | What date does the evidence describe? |
Appraisers may also consult their own records, builders, other appraisers, and specialized data providers. Access to a large database is useful, but the size of that database is not a substitute for understanding the transactions it contains.
What does it mean to verify a comparable sale?
Verification means resolving the facts that matter to the comparison, rather than assuming that every field in a listing is correct. The appraiser considers the source, how current it is, what it actually establishes, and whether another reliable source contradicts it. A participant’s statement can be valuable while still requiring additional support.
For example, a listing may describe an extensive renovation. Dated photographs can help show what was finished before closing. Permits or other records may clarify whether an addition existed at that time. A later photograph of a remodeled kitchen does not establish the kitchen’s condition on the earlier sale date.
For assignments subject to Fannie Mae requirements, the Selling Guide’s data and verification provisions call for specific sources and enough information to understand physical characteristics and transaction circumstances. Those are mortgage-program requirements, not a claim that every private appraisal uses an identical reporting form.
Questions behind the reported price
- Did the transaction close, or is the number an asking or pending price?
- What real estate and property rights were transferred?
- Were there seller credits, financing arrangements, or personal-property items?
- Was the home renovated before the sale or afterward?
- Were the parties related, or were there other circumstances needing explanation?
- Do the sale date, contract date, and recording date describe different events?
These questions help explain the evidence; they do not automatically disqualify a sale. An unusual transaction may still contain useful information if the circumstances are sufficiently understood and analyzed.
Why square footage deserves its own check
A property website, assessor record, and floor plan can show different area totals because of errors, different measurement methods, or different reporting categories. A total that combines a main house, finished basement, and detached room is not directly interchangeable with a figure describing only above-grade finished area.
The useful comparison starts with knowing what each figure includes. An appraiser may need to distinguish the main dwelling from a garage conversion, finished room over a garage, porch enclosure, or separate accessory space. An attractive room can contribute to the property without being reported in the same category as every other room.
See the explanation of ANSI measurement in applicable appraisal assignments. If your immediate concern is documenting the home’s dimensions before marketing, home measuring services can address that question without treating a measurement as an opinion of market value.
Verify the contract, closing, and recording dates
A sale can have several dates because the contract, closing, and recording are different events. Check which date a database displays, and seek the contract date where it matters to the analysis. Confirm whether listing photos and improvement records describe the property before the sale or after later work.
For a historical appraisal, records should help establish the property and transaction as they existed at the relevant time. A current photograph or a recently updated property card may not describe the earlier condition.
Once the dates and facts are verified, the separate guide to choosing comparable sales explains how far back appraisers look for comps and how they weigh location, timing, and property differences.
Check the property behind the map pin
Match the address to the correct parcel or condominium unit. Use the listing, assessor record, and recorded documents to investigate the property rights, access, and site characteristics. A map pin alone may not reveal shared access, an adjoining parcel, or whether advertised waterfront rights actually transferred.
These checks establish what sold. Deciding which verified sales best compete with the subject is the next stage, covered in the selection guide.
How verified facts become an adjustment
Once a relevant difference is established, the next question is whether buyers paid differently because of it. Construction cost, an owner’s preference, or the average sale price per square foot does not by itself establish a feature’s contributory value. Several pieces of evidence may be needed to separate a size difference from differences in condition, site, or location.
Fannie Mae’s adjustment guidance calls for market-supported analysis, including the effect of concessions where relevant. A seller credit is not automatically deducted dollar for dollar. The question is how the arrangement affected the transaction in its market.
The final opinion also is not necessarily the arithmetic average of three adjusted prices. The appraiser considers the strength of the underlying evidence and the relevance of each indication. A neatly calculated number cannot repair a weak or misunderstood data source.
Can an online estimate replace this research?
An automated estimate can be a starting reference, but the displayed number may not explain the condition, area definitions, sale terms, or assumptions behind it. Two services can give different estimates because their data and models differ. Agreement between them does not prove that an unrecorded addition or recently completed renovation has been recognized correctly.
The distinction is explained in how automated valuation models differ from an appraisal. The practical next step is to check the facts, not select whichever estimate best matches a desired price.
What homeowners can provide
A concise property-information packet helps the appraiser investigate efficiently. Include a dated improvement list, available plans or measurements, relevant permits, and information about known condition issues. Identify whether a document reflects the current property or an earlier stage of construction.
If you suggest a comparable, provide its address, the source of the information, and a specific reason it competes with your home. “Same layout and similar renovation date” is more useful than “It sold for the highest amount.” Point out factual differences openly, including features that may make your suggested sale superior.
For a lender appraisal, send documented concerns through the lender’s reconsideration-of-value process. For a privately commissioned report, contact the appraiser about a specific factual question. Neither route promises a change in value; both work better with clear evidence.
Questions about comparable-sale records
Can a sale without an MLS listing be used?
Potentially. A private or off-market transaction still needs reliable information about the property, terms, and circumstances. The absence of an MLS record makes verification more important; it does not alone prove that the sale is unusable.
Are tax assessments comparable sales?
No. An assessment is a tax-administration figure, while a comparable sale is a transaction. Assessor records can provide useful characteristics and transfer information, but the assessment itself is not a substitute for a verified sale price.
Why did the appraiser consider a lower-priced sale?
Relevance is determined by the property and transaction evidence, not whether a sale raises or lowers the conclusion. Considering a range of competitive evidence helps avoid selecting only transactions that support a predetermined answer.
What if a promising sale has conflicting information?
The conflict should be investigated in proportion to its importance. Depending on what can be established, the appraiser may explain a limitation, give the sale less weight, or select better evidence.