Key Takeaways
- Comp selection priority: location first, then condition, size, and features.
- The best comp is always in the same neighborhood, even if physical adjustments are larger.
- Use a minimum of three comps; five is preferred for investment-grade analysis.
- When ideal comps are unavailable, expand search parameters systematically rather than using poor comps.
Comp selection is the most consequential step in the sales comparison approach—the quality of your value conclusion depends entirely on the quality of the comps you choose. This lesson establishes the hierarchy of selection criteria, defines ideal comp characteristics, and provides practical guidance on determining how many comps are needed for a reliable analysis.
The Selection Hierarchy: Location > Condition > Size > Features
When multiple potential comps are available, prioritize selection using this hierarchy. Location is paramount because it cannot be changed: a comp in the same neighborhood is almost always superior to a closer physical match in a different neighborhood. Condition is second because it directly affects value and is often the largest adjustment factor. Size is third because per-square-foot adjustments are relatively reliable within a reasonable range (typically ±20% of subject size). Features (garage, pool, views, lot characteristics) are fourth because their value contributions can usually be estimated from market data. This hierarchy means a 1,500 SF comp in the same subdivision is generally better than a 1,800 SF comp that is a closer size match but located in a different neighborhood.
Why it matters: The best comp is always in the same neighborhood as the subject, even if it requires larger adjustments for physical differences. Location adjustments are the hardest to quantify accurately and introduce the most uncertainty into the analysis.
Ideal Comparable Criteria
The ideal comparable sale meets all of the following criteria: sold within the past 6 months (3 months in volatile markets), located within 0.5 miles of the subject in the same neighborhood, similar in gross living area (within 15-20% of subject), similar age (within 10 years), similar condition and quality, same property type (single-family to single-family), arm's-length transaction with conventional financing, and no unusual conditions of sale. In practice, you will rarely find comps that meet every criterion. The art of comp analysis is selecting the best available comps and making defensible adjustments for the differences that exist.
| Criterion | Ideal | Acceptable | Red Flag |
|---|---|---|---|
| Sale Date | 0-3 months | 3-12 months | > 12 months |
| Distance | < 0.5 mile | 0.5-1.0 mile | > 1 mile |
| Size (GLA) | ± 10% | ± 20% | > 20% difference |
| Age | ± 5 years | ± 10 years | > 15 years different |
| Condition | Same | Minor differences | Renovated vs. distressed |
| Transaction Type | Arm's length | Verified market sale | REO, short sale, related party |
Comparable selection criteria ranges
Why it matters: Understanding this concept is essential for making informed investment decisions.
Minimum 3-5 Comps
USPAP does not mandate a specific number of comps, but industry standard is a minimum of three, with five being preferred for investment-grade analysis. Three comps provide the minimum needed to establish a range and identify outliers. Five comps provide better statistical confidence and make the analysis more resilient to any single questionable comp. More is not always better—using eight or ten comps that require large adjustments is worse than using four excellent comps that closely match the subject. When you cannot find three comps meeting ideal criteria, you may need to expand the geographic search area, extend the time range, or consider different property types (e.g., comparing a duplex to similar-sized single-family homes with appropriate adjustments).
Why it matters: Understanding this concept is essential for making informed investment decisions.
Key Takeaways
- ✓Comp selection priority: location first, then condition, size, and features.
- ✓The best comp is always in the same neighborhood, even if physical adjustments are larger.
- ✓Use a minimum of three comps; five is preferred for investment-grade analysis.
- ✓When ideal comps are unavailable, expand search parameters systematically rather than using poor comps.
Sources
- Appraisal Institute — Sales Comparison Methods(2025-03-15)
- Fannie Mae — Appraisal Guidelines(2025-03-15)
Common Mistakes to Avoid
Selecting comparable properties based on price proximity to a desired value rather than true similarity.
Consequence: Circular reasoning confirms a predetermined conclusion instead of independently estimating market value.
Correction: Select comps based on physical and locational similarity, not on how close their prices are to your target.
Failing to adjust for differences in transaction conditions between comparable sales.
Consequence: Non-arm's-length sales, seller concessions, and financing terms can distort the comp set by 5-15%.
Correction: Verify transaction type and terms for all comps and make appropriate adjustments.
Test Your Knowledge
1.In Selecting Comparable Properties, what determines the reliability of a comparable sale?
2.What is the maximum recommended net adjustment for a single comparable sale?
3.How should the final value be determined from multiple adjusted comparable sales?