Principle of substitution

A buyer chooses between two similar homes

Scenario: Home A is listed at $520,000. Home B offers similar rights, location, condition, size, quality, and utility for $495,000 with similar closing terms.

1. Home B is a strong substitute under the stated facts.
2. A typical informed buyer has little reason to pay $25,000 more for Home A without another benefit.
3. The competing alternative creates downward pressure on Home A's market price.

Answer: Substitution suggests Home A must justify the premium or move toward the competitive alternative.

A nearby sale is not a substitute

Scenario: A sale is one block from the subject but is legally restricted to a different use and appeals to a different buyer group. A sale three miles away has the same permitted use, utility, and demand sources.

1. Distance alone does not define competition.
2. The nearby sale lacks legal and market-participant similarity.
3. The farther sale can be the better substitute, subject to supported location analysis.

Answer: Choose evidence based on competitive utility, not proximity alone.

New construction takes two years

Scenario: An existing specialized building is available now for $8 million. A modern equivalent appears to cost $7.5 million, but approvals and construction take two years and carry material cost and completion risk.

1. The $7.5 million construction figure is not an immediately available finished substitute.
2. Time, carrying cost, risk, interim occupancy, and entrepreneurial incentive affect the all-in alternative.
3. The existing property can rationally command more than bare construction cost.

Answer: Compare the full time- and risk-adjusted substitute cost, not the nominal build estimate alone.

Replacement avoids an obsolete feature

Scenario: The subject contains an obsolete service corridor. A modern equivalent building would provide the same utility with less area and a better layout.

1. Substitution focuses on equivalent utility rather than exact reproduction.
2. Replacement cost can omit the obsolete corridor from the modern substitute.
3. The appraiser coordinates remaining functional loss to avoid double counting.

Answer: Use equivalent modern utility in replacement analysis and reconcile any separate functional-obsolescence deduction.

The lowest price has higher operating risk

Scenario: Two rental properties have similar initial NOI. The cheaper property has major near-term capital needs, unstable tenants, and higher vacancy risk.

1. Nominal price does not measure the full benefit-and-risk package.
2. Capital cost, income durability, and tenant risk reduce its desirability.
3. An investor may pay more for the more stable substitute and still act prudently.

Answer: Compare risk-adjusted benefits and total ownership burden, not price alone.

A special purchaser sees assemblage value

Scenario: An interior parcel has ordinary value to most buyers but completes an adjoining developer's planned assemblage and unlocks unique density benefits.

1. The adjoining owner can receive a benefit unavailable to typical buyers.
2. Ordinary substitutes may not reproduce that assemblage position.
3. The transaction can reflect special value and requires careful market-value treatment.

Answer: Do not assume ordinary substitution fully explains a buyer-specific assemblage premium.

An older sale is the better alternative

Scenario: A ten-month-old sale matches the subject's rights, design, condition, utility, and buyer pool. A one-month-old sale is a luxury renovation serving a different segment.

1. Recency helps but does not replace competitive similarity.
2. The older sale is more representative of the choice facing subject buyers.
3. A supported market-condition adjustment can address time.

Answer: The older sale may deserve greater weight as the better substitute.

1. What does the principle of substitution state?

1. A prudent buyer generally will not pay more than the cost of an equally desirable alternative
2. Every nearby property has the same value
3. Cost always equals value
4. The oldest sale is best

2. Which approach applies substitution most visibly through comparable sales?

1. Sales comparison approach
2. Tax assessment only
3. Mortgage amortization
4. Title examination

3. How does the cost approach apply substitution?

1. It compares the subject with the full cost of creating an equally useful site and improvement
2. It ignores land and time
3. It always reproduces obsolete design
4. It uses mortgage balance as value

4. Must substitute properties be identical?

1. No, they must be competitively similar in overall utility
2. Yes, in every detail
3. Yes, but only in age
4. No, because differences never matter

5. Why can an existing property exceed bare new-construction cost?

1. The substitute may require land, indirect cost, time, risk, and entrepreneurial incentive
2. Cost never matters
3. Every seller sets market value
4. Depreciation increases cost

6. Which sale is automatically the best substitute?

1. None; selection depends on competitive utility and evidence
2. The closest sale
3. The newest sale
4. The highest sale

7. What is the key difference between substitution and conformity?

1. Substitution compares alternatives; conformity considers harmony with surroundings
2. They are identical
3. Substitution applies only to tax
4. Conformity applies only to loans

8. What can make a cheaper property a weaker substitute?

1. Higher capital needs, vacancy risk, and inferior rights
2. A lower list price alone
3. A newer photograph
4. A shorter address

9. A parcel unlocks unique assemblage value for one neighbor. What should be considered?

1. The neighbor may be a special purchaser with buyer-specific benefits
2. Every buyer receives the same assemblage value
3. The parcel has no substitutes under any definition
4. Land value must equal assessed value

10. What does current Fannie Mae comparable guidance emphasize?

1. Comparables should be competitive and appeal to the same market participants
2. Comparables must be identical
3. Only same-street sales are allowed
4. The newest sale always controls