9.2 Cost, Income, Regression, and Qualitative Comparisons

Expanding the Adjustment Toolkit (ECO IV.d–e)

Paired data is ideal when the market hands you clean twins. Real files—and exam vignettes—often do not. AQB ECO IV.d Quantitative adjustments therefore also lists:

1. Paired data (Section 9.1)
2. Cost analysis
3. Income capitalization
4. Regression / trend analysis

And IV.e Quantitative comparisons (wording on the outline; these techniques are largely qualitative or semi-quantitative ranking tools in practice language) includes:

1. Ranking analysis / bracketing
2. Relative comparison analysis
3. Interviews with market participants

Together, these methods answer: How do I support a grid adjustment or an overall superiority conclusion when a perfect pair does not exist?

Cost Analysis for Adjustment Support

Cost analysis uses cost of a component—usually depreciated or market-recognized contributory cost—as evidence of how much that component might contribute to price.

When Cost Support Is Appropriate

Link to principles: Contribution and increasing/decreasing returns still govern. Cost is a ceiling clue or support, not automatic market value of the feature.

Worked Cost-Support Example: Deck

• Cost new of a wood deck matching the subject: $12,000
• Effective age suggests ~25% depreciation for the deck component → depreciated cost ≈ $12,000 × 0.75 = $9,000
• Thin paired data in the neighborhood clusters around $8,000–$10,000 for similar decks
• Appraiser supports a $9,000 deck adjustment, citing cost less depreciation corroborated by limited pairs

Exam contrast: If undepreciated cost is $12,000 but every sale shows only $5,000 contribution for older decks, the correct adjustment leans $5,000 market contribution, not $12,000 cost. Cost analysis that ignores depreciation and market reaction fails.

Cost Support for Condition / Deferred Maintenance

Buyers often price obvious repairs as concessions or lower offers. An appraiser may support a condition adjustment using cost to cure for items a typical buyer would fix immediately (broken HVAC, failed roof section), provided the market actually behaves that way. Do not double-count the same defect as both a huge condition adjustment and a separate “expenditures after sale” transactional adjustment without a coherent story.

Income Capitalization Support for Adjustments

For income-producing residential (small multifamily) or commercial properties, a difference in rent or NOI can be capitalized into a value difference that supports an SCA line item.

GRM / Rent Difference Method (Residential Income Style)

Indicated value difference ≈ Monthly rent difference × Gross Rent Multiplier (GRM)

(Use the multiplier form consistent with the data: monthly GRM vs annual GIM—do not mix.)

Worked example:

• Market monthly GRM for similar duplexes: 120
• Subject market rent: $2,400/month (both units)
• Comparable duplex rent: $2,250/month (inferior income)
• Rent gap: $150/month
• Indicated adjustment support: $150 × 120 = $18,000 upward to the comparable if physical/income-producing capacity is the only material gap and GRM is applicable

Direct Capitalization of NOI Difference

Value difference ≈ NOI difference ÷ capitalization rate

Worked example:

• Market OAR (cap rate): 8% (0.08)
• Subject stabilized NOI: $80,000
• Comparable’s NOI at same vacancy/expense standard: $76,000
• NOI gap: $4,000
• Indicated value gap: $4,000 ÷ 0.08 = $50,000

If the comparable sold at a price that already reflects its lower income, this $50,000 supports how much to adjust when matching the subject’s income-producing ability—provided income differences are not already fully reflected in another grid element and the cap rate is market-supported for the type.

Caution: Income-based adjustment support assumes the income difference is stable and market-recognized, not a temporary lease anomaly. Fee simple market-rent analysis may be required when leased fee rents are atypical.

Regression and Trend Analysis Overview

Regression analysis fits a statistical relationship between sale prices (dependent variable) and one or more property or market variables (independent variables). Trend analysis often refers to tracking price change over time (market conditions) or simple linear relationships with size.

On the National Exam you need conceptual competence more than software output:

Worked Trend (Market Conditions) Micro-Example

Comparable sales show the following average closed prices for similar product:

Increase: $24,000 / $400,000 = 6% over 6 months ≈ 1% per month if a constant monthly rate is a reasonable simplification.

A comparable that sold 3 months ago for $410,000 might receive a market-conditions adjustment of approximately 3 × 1% = +3% → 0.03 × $410,000 = +$12,300 (compounding conventions vary; exam stems usually keep it simple with straight percentage).

Worked Simple Size Slope Concept

If a scatter of 20 similar sales suggests price rises about $90 per additional square foot of GLA holding other factors roughly constant, that slope can support a GLA adjustment near $90/sq ft—especially when paired data are scarce. You still exclude outliers, verify the sample matches the subject’s segment, and avoid over-precision (“$87.43 exactly”) when the cloud is wide.

Exam traps for regression/trend:

• Small samples dressed up as “models”
• Omitting major variables (location) so coefficients absorb the wrong effect
• Extrapolating far outside the data range
• Using trends from a different market tier
• Confusing correlation with a usable adjustment without appraisal reasoning

Ranking Analysis and Bracketing

Ranking analysis orders comparables (and sometimes the subject) from inferior to superior for overall desirability or for a specific feature. Bracketing means the subject’s characteristics and the final value opinion are set between comparables that are better and worse, or higher and lower in price, so the conclusion is not extrapolated beyond the evidence.

Example: Subject is average quality. Comp 1 is clearly superior (adjusted $510,000). Comp 2 is clearly inferior (adjusted $470,000). Comp 3 is most similar (adjusted $488,000). Ranking supports a subject value inside $470,000–$510,000, weighted toward Comp 3—not $530,000 above the superior sale without new evidence.

Bracketing is both a data selection goal and a reconciliation discipline (Section 9.3).

Relative Comparison Analysis

Relative comparison analysis is a systematic qualitative technique: for each major element, the appraiser rates the comparable as superior, inferior, or similar to the subject (sometimes with +/− or ++/−− intensity), then forms an overall net comparison without necessarily assigning every dollar on every line.

If Comp 1 sold for $500,000 and is slightly superior overall, the subject is indicated somewhat under $500,000. If Comp 2 sold for $480,000 and is slightly inferior, the subject is indicated somewhat over $480,000. The relative array brackets the subject even when a full quantitative grid is incomplete.

Relative comparison is not an excuse to skip research. It is the honest method when the market does not isolate clean dollars for every line—common for view, cul-de-sac prestige, or minor design differences.

Market Participant Interviews

Interviews with market participants—buyers, sellers, brokers, builders, lenders—are recognized under ECO IV.e.3. They provide primary market evidence about:

• Whether a feature was a negotiating point and roughly how much it mattered
• Typical concessions and financing in the current market
• Why a sale was unusually high or low
• Absorption, listing strategies, and buyer preferences

Exam warning: An interview alone is usually weaker than a closed-sale pair, but a documented interview can explain a sale or support a qualitative ranking when pairs are unavailable. Fabricated precision (“exactly $14,250 because a broker guessed”) is not better analysis.

Choosing Among Methods — Decision Table

Integrated Mini Case

Subject: 1,650 sq ft, 2-bath, 1-car garage, average condition, no pool. Market has few perfect pairs.

• Garage: One imperfect pair suggests ~$15,000; depreciated cost of 1-car garage ~$18,000; brokers say “low to mid teens.” Appraiser uses $15,000 with dual support (pair + interview), notes cost as upper reference.
• Pool on Comp 5: Cost new $40,000; local pairs for pools weak; interviews say many buyers indifferent in this price tier; one sale suggests ~$10,000. Appraiser avoids $40,000 cost adjustment; uses $10,000 or treats pool in qualitative net if support remains thin.
• Time: MLS trend shows ~0.5%/month increase for 4 months → support for market conditions line via trend analysis.
• View: No dollar pair; Comp 3 has inferior view. Appraiser marks inferior on relative comparison and weights Comp 3 below more similar sales in reconciliation rather than inventing $27,000.

This is how ECO IV.d and IV.e work together: quantitative when the market speaks in numbers, qualitative when it speaks in ranks—both aimed at a credible indicated value by SCA (next section).