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COURSE 311
Real Property Modeling Concepts
Solutions Set
Real Property Modeling Concepts | Course 311
Solutions Set 2
© 2020 International Association of Assessing Officers
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Chapter 1 - Solutions Set 3
© 2020 International Association of Assessing Officers
Chapter 1 | Introduction to Mass Appraisal
REVIEW QUESTIONS – Chapter 1 SOLUTION
1. The definition of mass appraisal is the systematic appraisal of groups of properties, as of a given date,
using standardized procedures and statistical testing.
2. Characteristics of mass appraisal that are different from single property appraisal are the use of
valuation tables, schedules, and models.
3. Economic, social, and environmental data are termed market data, while off-site features and
improvement data are termed property analysis data.
4. The appraisal principle which states “land cannot be valued on the basis of one use, while
improvements are valued on the basis of another use” is the principle of consistent use.
5. Selecting appropriate valuation approaches and specifying the variables to be used is called model
specification.
6. Developing adjustment weights from measurable supply and demand factors, including quantitative
and qualitative factors, is called model calibration.
7. According to modern price theory, value in exchange is determined by the interaction of supply and
demand.
8. List the three determinants of supply and the five determinants of demand.
Supply Demand
Price Price
Availability and cost of related goods Consumers’ income
Technology Price of related commodities
Consumer expectations
Consumer tastes and preferences
9. V = bo + b1 × SFLA + b2 × #baths + b3 × GARSQFT … is an example of a/an additive model.
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Chapter 1 - Solutions Set 4
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Real Property Modeling Concepts | Course 311
Chapter 2 – Solutions Set 5
© 2020 International Association of Assessing Officers
Chapter 2 | Data Collection and Management
Exercise 2-1: Creation of Binary Variables – Solution
You are appraising an area where lot size requires an adjustment based on size ranges. Your analysis has
indicated the following:
• Undersized lot = Less than 8,000 sq. ft.
• Standard lot = 8,000 to 12,000 sq. ft.
• Large lot = 12,001 to 16,000 sq. ft.
• Extra-large lot = 16,001 to 20,000 sq. ft.
• Double lot = Greater than 20,000 sq. ft.
1. How many binary variables are necessary to model the above lot sizes?
Five binary variables are created, but only four binary variables are necessary for these lot
sizes, for modeling purposes. In this problem, the presumption is that the standard lot is typical.
Variables for the other lot sizes are created and included in the model. The reference for these
coefficients will be the standard lot.
2. If the condition were met, how would you code the variable?
If the condition were met, the variable would be coded a 1.
3. If the condition were not met, how would you code the variable?
If the condition were not met, the variable would be coded a 0.
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Chapter 2 – Solutions Set 6
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Real Property Modeling Concepts | Course 311
Chapter 2 – Solutions Set 7
© 2020 International Association of Assessing Officers
Exercise 2-2: Creation of Scalar Variables – Solution
1. Develop scalar variables for each neighborhood for use in a multiplicative or hybrid model.
Since neighborhood 300 is considered the typical neighborhood, the scalar variables for a
multiplicative or hybrid model are developed by dividing each of the neighborhood’s average
sale price per square foot by the average sale price per square foot for Neighborhood 300. This
produces the following relative values:
Neighborhood 500 41 ÷ 50 = 0.82
Neighborhood 100 44 ÷ 50 = 0.88
Neighborhood 300 50 ÷ 50 = 1.00
Neighborhood 200 57.50 ÷ 50 = 1.15
Neighborhood 400 62.50 ÷ 50 = 1.25
2. Develop scalar variables for an additive model.
To create scalar variables for an additive model the values would be centered on 0 (by
subtracting 1.00) as follows:
Neighborhood 500 0.82 – 1.00 = -0.18
Neighborhood 100 0.88 – 1.00 = -0.12
Neighborhood 300 1.00 – 1.00 = 0
Neighborhood 200 1.15 – 1.00 = + 0.15
Neighborhood 400 1.25 – 1.00 = + 0.25
Real Property Modeling Concepts | Course 311
Chapter 2 – Solutions Set 8
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Real Property Modeling Concepts | Course 311
Chapter 2 – Solutions Set 9
© 2020 International Association of Assessing Officers
1. Assume that the standard home is 1,500 square feet. Compute a size multiplier for the following
benchmark parcels by raising square foot of living area to the power of 0.90 and expressing the
results relative to the standard home. (Note: This requires a calculator with a power key.)
SQFT SQFT0.90 MULTIPLIER
1,000 501 0.694
1,500 722 1.000
2,000 935 1.295
2,500 1,143 1.583
3,000 1,347 1.866
Sample equation: 1,0000.90 = 501 ÷ 722 = 0.694
2. Assume that property values are heavily influenced by their proximity to the ocean and that the effect
can be approximated by raising distance to the power of -0.50. Compute the appropriate multiplier
for the following distances. (Note: If you don't have a calculator with power key, take the square root
and then the reciprocal of the result).
MILES MILES-0.50
0.10 3.162
0.25 2.000
0.50 1.414
1.00 1.000
2.00 0.707
5.00 0.447
Exercise 2-3: Exponential Transformations – Solution
Real Property Modeling Concepts | Course 311
Chapter 2 – Solutions Set 10
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Chapter 2 – Solutions Set 11
© 2020 International Association of Assessing Officers
Exercise 2-4: Logarithmic Transformations – Solution
Find the natural logs of the following depths and express the result relative to the standard depth (100
feet).
DEPTH NATURAL LOG FACTOR
50 3.912 0.850
75 4.317 0.937
100 4.605 1.000
125 4.828 1.048
150 5.011 1.088
175 5.165 1.122
200 5.298 1.150
Each doubling of the amount of depth provides an equal increase in the logarithm. For example, a
change from a depth of 50 feet to a depth of 100 feet equals 0.693 (4.605 - 3.912 = 0.693) and a
change from a depth of 100 feet to a depth of 200 feet equals 0.693 as well (5.298 - 4.605 = 0.693).
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Chapter 2 – Solutions Set 12
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Chapter 2 – Solutions Set 13
© 2020 International Association of Assessing Officers
REVIEW QUESTIONS – Chapter 2 SOLUTION
1. List the four market forces that must be analyzed.
Economic Governmental Social Physical / Environmental
2. Items such as building codes, planning, and zoning are considered governmental forces.
3. The most effective, yet most expensive, method of gathering income and expense data is personal
interviews.
4. Potential gross income (PGI) is based on market rent, which reflects current rents and typical
management.
5. Net operating income is the income that is typically capitalized into an indication of value in mass
appraisal.
6. Typically, a gross lease requires the owner to pay all operating expenses, while a net lease requires
the tenant to pay all operating expenses.
7. Qualitative data, also known as "discrete" data, relate to features or attributes of the property.
8. Quantitative data, also known as "continuous" data, are based on measuring or counting.
9. Scalar transformation converts a discrete variable to relative values or numerical ratings.
10. When property characteristics affect value interactively, a multiplicative transformation captures the
interactive effects.
11. A pilot study helps evaluate what data to collect and the best way to collect them.
12. IAAO standards recommend routine property inspections at least every six (6) years.
13. List four methods of obtaining income and expense data:
Mail questionnaires Telephone interview
Personal interview Industry and trade publications
14. The square foot area of a residence is considered continuous (quantitative) data while the condition
rating is considered discrete (qualitative) data.
15. Binary data are qualitative items that have only two possibilities: yes or no.
16. The result of a depreciation analysis shows that the effect of age or value is: % good = Age-0.l0. The
percent good for 20 years of age would be 0.741 while the percent good for 40 years of age would
be 0.692.
17. The natural log for a lot with a depth of 150 feet would be 5.011. The adjustment factor for this lot
relative to a base lot of 100 feet would be 1.088.
18. A multiplicative transformation helps address the interactive relationship of a size-related variable
with a quality-related variable.
19. The division of one variable by another, for example square feet by number of rooms, is termed a
quotient transformation.
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Chapter 2 – Solutions Set 14
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Real Property Modeling Concepts | Course 311
Chapter 3 – Solutions Set 15
© 2020 International Association of Assessing Officers
Chapter 3 | Market Analysis
INTERVAL NUMBER OF
OCCURRENCES
FREQUENCY DISTRIBUTION
(% OF SALES)
1940 and Before 3 6%
1941–1950 6 12%
1951–1960 8 16%
1961–1970 16 32%
1971–1980 7 14%
1981–1990 6 12%
1991 and After 4 8%
Exercise 3-1: Constructing A Frequency Distribution – Solution
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Chapter 3 – Solutions Set 17
© 2020 International Association of Assessing Officers
DATA # SALE PRICE $ K = (p)(n) + p
1 89,500
2 91,000
3 93,000
4 95,500
5 97,000 25%
(.25)(20) + .25 = 5.25
1500 x .25 = 375 + 97,000 = 97,375 6 98,500
7 99,500
8 100,000
9 100,800
10 101,400
11 102,500
12 103,200 60% (.60)(20) + .60 = 12.60
800 x .60 = 480 + 103,200 = 103,680 13 104,000
14 105,000
15 107,000 75% (.75)(20) + .75
1500 x .75 = 1,125 + 107,000 = 108,125 16 108,500
17 110,000
18 112,000
19 114,000
20 116,000
Exercise 3-2: Calculation of Percentile – Solution
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Chapter 3 – Solutions Set 19
© 2020 International Association of Assessing Officers
Exercise 3-3: Computing Measures of Central Tendency and Dispersion – Solution
MEAN
PROPERTY
NUMBER
EFFECTIVE AGE EFFECTIVE AGE DIFFERENCE
FROM MEAN
DIFFERENCE
SQUARED
1 24 30 -6 36
2 26 30 -4 16
3 28 30 -2 4
4 29 30 -1 1
5 30 30 -0- -0-
6 30 30 -0- -0-
7 31 30 +1 1
8 32 30 +2 4
9 34 30 +4 16
10 36 30 +6 36
TOTAL 300 114
Median effective age: (30 + 30) ÷ 2 = 30
Mean effective age: 300 ÷ 10 = 30
Range: 36 – 24 = 12
Variance: 114 ÷ 9 = 12.67
Standard Deviation: 67.12 = 3.56
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Chapter 3 – Solutions Set 21
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Exercise 3-4: Confidence Intervals – Solution
PARCEL EFFECTIVE
AGE MEAN DIFF
SQRD
DIFF
1 20 30.20 -10.20 104.04
6 21 30.20 -9.2 84.64
2 22 30.20 -8.2 67.24
3 25 30.20 -5.2 27.04
7 29 30.20 -1.2 1.44
4 30 30.20 -0.2 .04
10 30 30.20 -0.2 .04
13 30 30.20 -0.2 .04
8 31 30.20 0.8 .64
14 31 30.20 0.8 .64
11 33 30.20 2.8 7.84
9 36 30.20 5.8 33.64
15 38 30.20 7.8 60.84
5 38 30.20 7.8 60.84
12 39 30.20 8.8 77.44
Sum 453 Sum 526.40
Median effective age: 30.00
Mean effective age: 30.20
Standard deviation: 6.13
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Chapter 3 – Solutions Set 22
© 2020 International Association of Assessing Officers
Exercise 3-4: Confidence Intervals – Solution (continued)
The confidence interval for the mean is:
�̅� ± 𝑡 × (𝑆 ÷ √𝑛)
30.20 ± 2.145 × (6.13 ÷ 3.87)
30.20 ± 3.40
The lower confidence limit is 30.20 – 3.40 = 26.80
The upper confidence limit is 30.20 + 3.40 = 33.60
The confidence interval for the median is:
𝑗 =1.96 × √15
2
𝑗 =1.96 × 3.87
2
j = 3.79 or 4
The lower confidence interval is 25.
The upper confidence interval is 36.
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Chapter 3 – Solutions Set 23
© 2020 International Association of Assessing Officers
Exercise 3-5: Hypothesis Tests – Solution
SALE
NUMBER
SALE
DATE
SALE
PRICE $
SALE
DATE
SALE
PRICE $
AMOUNT
OF
CHANGE
MONTHLY
RATE OF
CHANGE
1 16 months 118,300 current 132,000 0.1158 0.0072
2 15 months 110,500 current 123,900 0.1213 0.0081
3 14 months 145,100 current 174,000 0.1992 0.0142
4 11 months 138,600 current 149,000 0.0750 0.0068
5 19 months 149,700 current 187,000 0.2492 0.0131
6 22 months 120,300 1 month 134,900 0.1214 0.0058
7 19 months 144,500 1 month 150,000 0.0381 0.0021
8 21 months 148,300 3 months 166,600 0.1234 0.0069
9 33 months 120,900 1 month 128,000 0.0587 0.0018
10 34 months 111,000 3 months 123,000 0.1081 0.0035
SUM 0.0695
AVERAGE 0.00695
The t-test formula is: Average = mean of monthly rates ± 𝑡 × (𝑠𝑡𝑎𝑛𝑑𝑎𝑟𝑑 𝑑𝑒𝑣𝑖𝑎𝑡𝑖𝑜𝑛 ÷ √𝑛)
Average = 0.00695 ± 1.833 × (0.00415 ÷ √10)
Where 1.833 is the one-tailed t-value corresponding to the 95% confidence interval with 9 degrees of
freedom.
Average = 0.00695 ± 1.833 × (0.00415 ÷ 3.162)
Average = 0.00695 ± 1.833 × .0013124
Average = 0.00695 ± 0.0024077
0.00695 – 0.0024077 = 0.00454
0.00695 + 0.0024077 = 0.00936
Confidence Interval = 0.00454 to 0.00936
Since the computed confidence interval is above zero and positive, we reject Ho.
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Chapter 3 – Solutions Set 25
© 2020 International Association of Assessing Officers
Exercise 3-6 Hypothesis Tests – Solution
Average sale price ± t × (standard deviation ÷ square root of number of observations)
�̅� ± 𝑡 × (𝑆 ÷ √𝑛)
$97,000 ± 1.96 × (15,000 ÷ √225)
$97,000 ± 1.96 × (15,000 ÷ 15)
$97,000 ± 1.96 × 1,000
$97,000 ± 1,960
$95,040 to $98,960
Because the range in sales prices does not include $100,000, you must reject the null hypothesis and
accept the alternative hypothesis.
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Chapter 3 – Solutions Set 27
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REVIEW QUESTIONS – Chapter 3 SOLUTION
1. Market or economic areas are broad geographic areas subject to similar economic influences.
2. Subareas or neighborhoods are groups of properties that share similar location amenities.
3. Market areas are used primarily in the development of MRA models, while subareas are used to
develop regression variables.
4. Stratification criteria to be considered, in addition to property type and location, can include such things as
size, age, condition, and quality.
5. A method of stratification operating on the principle of minimizing differences within groups and
maximizing differences among groups is known as cluster analysis.
6. A histogram is a bar chart or graph of a frequency distribution.
7. Percentiles are those values that include given percentages of the data set.
8. Quartiles are those values that include one-fourth, one-half, three-fourths, and 100 percent of the
data, respectively.
9. When data are normally distributed, approximately 68 percent lie within one standard deviation, 95
percent within two standard deviations, and 99 percent within three standard deviations of the mean.
10. Common measures of central tendency in market analysis are the mean, median, and mode.
11. Two common measures of dispersion in market analysis are the range and the standard deviation.
12. Cross-tabulation shows the relationship between two qualitative variables or grouped quantitative
variables.
13. Correlation analysis quantifies the degree of linear relationship between two variables.
14. Polygons also called line charts can be used to show several variables simultaneously.
15. The analysis of a continuous variable with two qualitative variables can be accomplished using
contingency tables or three-dimensional plots.
16. One of the most common statistical tests that is used to determine whether the mean equals a given
value is the t-test.
17. In testing variables, two primary statistical tests can be used. However, a parametric test assumes
that the data are normally distributed, while a non-parametric test requires no assumption about the
distribution of the data.
18. A polygon plots summary statistics for a continuous variable against a second or third variable.
19. Confidence intervals are valuable to assessors, because they provide meaningful information about
the probable range of the true measures of central tendency.
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Chapter 3 – Solutions Set 28
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Real Property Modeling Concepts | Course 311
Chapter 4 – Solutions Set 29
© 2020 International Association of Assessing Officers
Chapter 4 | Ratio Studies
Exercise 4-1: Calculating Measures of Central Tendency – Solution
Sale
Number
Appraised
Value
Sale Price Ratio
4 $ 90,000 $120,000 0.75
3 $79,900 $94,000 0.85
2 $82,800 $92,000 0.90
7 $95,000 $100,000 0.95
5 $102,900 $98,000 1.05
6 $109,200 $104,000 1.05
1 $126,500 $110,000 1.15
TOTALS $686,300 $718,000 6.70
Mean Ratio: 6.70 ÷ 7 = 0.957
Median Ratio: 0.950
Weighted Mean Ratio: 686,300 ÷ 718,000 = 0.956
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Chapter 4 – Solutions Set 31
© 2020 International Association of Assessing Officers
Exercise 4-2: Calculating the Coefficient of Dispersion – Solution
Use the data from Exercise 4-1 and compute the coefficient of dispersion based on the median ratio.
Sale
No. Ratio
Median
Ratio
Average Absolute
Deviation
4 0.75 0.95 0.20
3 0.85 0.95 0.10
2 0.90 0.95 0.05
7 0.95 0.95 0.00
5 1.05 0.95 0.10
6 1.05 0.95 0.10
1 1.15 0.95 0.20
--- --- --- 0.75
Averaged Absolute Deviation: 0.75 ÷ 7 = 0.107
Coefficient of Dispersion: (0.107 ÷ 0.95) × 100 = 11.26%
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Chapter 4 – Solutions Set 33
© 2020 International Association of Assessing Officers
Exercise 4-3: Calculating the Coefficient of Variation – Solution
SALE
NO. RATIO
DIFF.
FROM
MEAN
DIFF.
SQUARED
SALE
NO. RATIO
DIFF.
FROM
MEAN
DIFF.
SQUARED
1 0.79 -0.17 0.0289 11 0.97 0.01 0.0001
2 0.88 -0.08 0.0064 12 0.70 -0.26 0.0676
3 1.06 0.10 0.0100 13 0.75 -0.21 0.0441
4 1.15 0.19 0.0361 14 1.02 0.06 0.0036
5 0.99 0.03 0.0009 15 1.05 0.09 0.0081
6 0.99 0.03 0.0009 16 1.12 0.16 0.0256
7 0.90 -0.06 0.0036 17 1.20 0.24 0.0576
8 0.96 0.00 0 18 1.15 0.19 0.0361
9 0.85 -0.11 0.0121 19 1.05 0.09 0.0081
10 0.75 -0.21 0.0441 20 0.95 -0.01 0.0001
TOTAL 0.3940
Standard deviation: 0.3940 ÷ 19 (n-1) = 0.0207
√𝟎. 𝟎𝟐𝟎𝟕 = 0.144
Coefficient of variation: (0.144 ÷ 0.96) × 100 = 15.00%
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Chapter 4 – Solutions Set 35
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Exercise 4-4: Calculating Sales Ratio Statistics – Solution
SALE NO. SALE RATIO
ARRAYED MEDIAN
ABSOLUTE
DEVIATION
MEDIAN
MEAN DEVIATION DEVIATION
SQUARED
4 0.70 0.98 0.28 0.95 -0.25 0.0625
9 0.75 0.98 0.23 0.95 -0.20 0.0400
7 0.79 0.98 0.19 0.95 -0.16 0.0256
5 0.90 0.98 0.08 0.95 -0.05 0.0025
1 0.97 0.98 0.01 0.95 +0.02 0.0004
10 0.99 0.98 0.01 0.95 +0.04 0.0016
3 1.02 0.98 0.04 0.95 +0.07 0.0049
8 1.06 0.98 0.08 0.95 +0.11 0.0121
2 1.12 0.98 0.14 0.95 +0.17 0.0289
6 1.20 0.98 0.22 0.95 +0.25 0.0625
TOTAL 9.50 ---- 1.28 TOTAL ---- 0.2410
Mean: 9.50 ÷ 10 = 0.95
Median: (0.97 + 0.99) ÷ 2 = 0.98
Weighted mean: 952,750 ÷ 1,025,000 = 0.93 (rounded)
Coefficient of dispersion: 1.28 ÷ 10 = 0.128 (Average Absolute Deviation)
(0.128 ÷ 0.98) × 100 = 13.06%
Coefficient of variation: 0.2410 ÷ 9 = 0.0268
√0.0268 = 0.1637 (SD)
(0.1637 ÷ 0.95) × 100 = 17.23%
Price-related differential: 0.95 ÷ 0.93 = 1.02 (rounded)
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Chapter 4 – Solutions Set 37
© 2020 International Association of Assessing Officers
REVIEW QUESTIONS – Chapter 4 SOLUTION
1. List three uses for ratio studies:
Testing compliance with legal or administrative standards
Identifying groups of properties requiring reappraisal or adjustments
Evaluating the effectiveness of various appraisal procedures
Monitoring the work of individual appraisers
Gauging the merit of taxpayer appeals
2. The preferred measure of assessment level in most ratio studies is the median.
3. Which measure of the central tendency weights each ratio in proportion to its sale price?
the weighted mean
4. The coefficient of dispersion (COD) is the most widely used measure of uniformity in ratio studies.
5. The IAAO standard for the coefficient of dispersion (COD) for residential properties is between 5 and
10 for properties in newer relatively homogeneous areas and between 5 and 15.0 in older
heterogeneous areas.
6. The coefficient of variation (COV) expresses the standard deviation as a percentage, making
comparisons among groups easier.
7. The predictive power of the coefficient of variation (COV) depends on the extent the data are
normally distributed.
8. A scatter diagram depicting the relationship between sales ratio and effective age that portrays a
downward sloping trend indicates a negative correlation which reflects lower ratios for older
residences.
9. The price-related differential (PRD) is calculated by dividing the mean by the weighted mean.
10. PRDs greater than 1.03 indicate relative under appraisal of higher value parcels while PRDs less than
0.98 indicate relative over appraisal of higher value parcels.
11. The price-related differential relates to equality between lower and higher value parcels.
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Real Property Modeling Concepts | Course 311
Chapter 5 – Solutions Set 39
© 2020 International Association of Assessing Officers
Chapter 5 | Cost Approach
REVIEW QUESTIONS – Chapter 5 SOLUTION
1. In the cost approach model, construction costs represent the supply side of the market, while
depreciation represents the demand side of the market.
2. The first step in specifying cost models is to stratify improvements into homogeneous groups.
3. In developing a cost table, a scatter diagram is used to develop the relationship between the cost
per square foot and area.
4. Adjustments for variations from base specifications in the cost model can take the form of
multipliers, dollars per square foot, other per unit costs, or lump sum dollar costs.
5. List three types of sales that should be excluded when deriving depreciation schedules from the
market:
Mixed-use parcels
Parcels with additional buildings
Parcels with extreme land-to-building ratios
6. After plotting percent good or accrued depreciation against effective age, a curve can be fitted to the
data using any one of the following three ways:
Visually by hand
Using graphics software
Using multiplicative or nonlinear MRA
7. Market calibration of cost models is best accomplished by using ratio studies or through multiple
regression analysis (MRA).
8. The cost approach attempts to replicate the workings of the real estate market, since the current cost
of construction represents the supply side and depreciation and variations in location represent the
demand side of the market.
9. In the following cost model V = GQ [LV + (RCN-D)], GQ represents general qualitative factors.
10. In structuring models for commercial properties, stratification is usually based on structure type and
number of floors.
11. For commercial properties, construction costs are usually divided between structural and interior
costs.
12. In the following cost model, V = πGQ × [1-BQD) × RCN +LV], the symbol BQD represents
depreciation.
13. To calibrate a model to produce Replacement Cost New (RCN), replacement costs must include all
direct and indirect costs.
14. Cost schedules should be tested to ensure that estimated costs are consistent with actual (local)
costs.
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Chapter 5 – Solutions Set 40
© 2020 International Association of Assessing Officers
15. Formula-driven cost models are an equation that expresses additive adjustments as multipliers.
16. In developing building depreciation schedules, percent good or accrued depreciation is plotted
against effective age.
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Quiz 1 – Solutions Set 41
© 2020 International Association of Assessing Officers
Quiz 1 Solutions
1. Scalar values are best centered on 1.00 in:
A. Additive models
B. Multiplicative models
C. Hybrid models
D. All of the above
2. Which of the following statistical techniques would be most appropriate for
grouping similar subdivisions for modeling purposes?
A. Multiple regression analysis
B. Location Value Response Surface Analysis
C. Adaptive estimation procedure
D. Cluster analysis
3. Assume that the average age of homes in a neighborhood is 25 years and that the
standard deviation is 3 years. Assuming the data are normally distributed,
approximately 95% of the homes will fall in what age bracket?
A. 22-26
B. 22-28
C. 19-31
D. 16-34
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Quiz 1 – Solutions Set 42
© 2020 International Association of Assessing Officers
4. A scatter diagram shows that there is a loose negative correlation between sale
price and distance to the central business district. Which of the following
correlation coefficients would be consistent with the scatter diagram?
A. Zero
B. -2.00
C. -.20
D. .50
5. Which of the following best defines the coefficient of dispersion (COD)?
A. Average deviation from the chosen measure of central tendency
B. Standard deviation of the ratios expressed as a percentage of the mean
C. The range which contains 50 percent of the ratios
D. Average percentage deviation from the median
6. The IAAO standards for the COD for older, heterogeneous residential property is:
A. 5.0 or less
B. 10.0 or less
C. 15.0 or less
D. 20.0 or less
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7. Assessors need skills in single property appraisal to:
A. Develop valuation models
B. Test values
C. Defend values
D. All of the above
8. In a statistical test, the statement or conclusion that is accepted in the absence of
sufficient evidence to the contrary is known as the:
A. First hypothesis
B. Alternative hypothesis
C. Confidence level
D. Null hypothesis
9. Consider the following ratios: .89, .96, 1.08, 1.14, and 1.20. What is the coefficient of
variation (COV)?
A. 10.6
B. 11.4
C. 12.1
D. 13.3
10. In the cost approach model, construction costs represent the ____________ side of
the market and depreciation represents the _____________ side of the market.
A. demand - supply
B. supply - demand
C. supply – supply
D. demand - demand
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11. The cost approach is closely related to a/an:
A. Additive model structure
B. Multiplicative model structure
C. Hybrid model structure
D. Least square model structure
12. Which of the following is not one of the seven major steps in the mass appraisal
process?
A. Preliminary survey and analysis
B. Defend value estimates
C. Valuation
D. Correlation of values, model testing, and quality control
13. _________________________ is the process of quantifying and evaluating the reliability
of value estimates by comparing values to a representative sample of sales.
A. Model specification
B. Model calibration
C. Model testing
D. Model infusion
14. In modern price theory, which of the following is not a determinant of demand?
A. Consumer incomes
B. Price of related commodities
C. Consumer expectations
D. Availability and cost of goods used in the production process
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15. The following model structure: V = b0 + (b1*1) + (b2*X2) + (b3*X3)...
is what type of model?
A. Additive
B. Multiplicative
C. Hybrid
D. None of the above
16. Which of the following is the most effective but expensive means of collecting
income and expense data?
A. Mail questionnaire
B. Personal interview
C. Telephone
D. Assessment appeals
17. In a net lease the owner pays:
A. All expenses
B. Only operating expenses
C. A pre-specified percentage of operating expenses
D. No operating expenses
18. A lease indexed to the Consumer Price Index is an example of:
A. A percentage lease
B. An adjustable lease
C. A graduated lease
D. A net lease
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19. Interactive effects, in which the impact of certain property characteristics upon
value is interrelated, are best handled by:
A. Additive MRA
B. Stepwise MRA
C. Exponential transformations
D. Multiplicative and quotient transformations
20. Which of the following can best be used to present visually the contents of a
frequency distribution?
A. Array
B. Bar chart (histogram)
C. Scatter diagram
D. Box plot
21. The IAAO Standard on Ratio Studies calls for a price-related differential in what
range?
A. 0.95 to 1.05
B. 0.95 to 1.10
C. 0.98 to 1.03
D. 0 to 0.15
22. Costs used in mass appraisal are typically:
A. Reproduction costs
B. Replacement costs
C. Historical costs
D. Trended historical costs
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23. Which of the following does not apply to the development of depreciation tables?
A. Use only arm's-length sales
B. Exclude parcels with extreme land-to-building ratios
C. Include mixed-use parcels
D. Exclude parcels with additional buildings
24. In the market calibration of cost models, market adjustments can be developed
using ratio studies by:
A. Construction class
B. Size
C. Age groups
D. All of the above
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Chapter 6 | Sales Comparison Approach
Exercise 6-1: Calculating an Additive Model – Solution
Characteristics of the subject property:
Main living area 1,800 square feet
Finished basement area 1,200 square feet
Unfinished basement area 400 square feet
Garage area 528 square feet
Grade 3
Fireplace 1
Effective age 20
Location Neighborhood 2
Determine a value for the subject property by using the model given in Practical Application 6-1.
Then:
V = 20,965 + (43.19 × 1,800) + (22.96 × 1,200) + (10.04 × 400) + (19.40 × 528) + (6,444 × 3) +
(3,900 × 1) – (798 × 20) – (5,679 × NBHD2)
V = 20,965 + 77,742 + 27,552 + 4,016 + 10,243 +19,332 + 3,900 – 15,960 – 5,679 = $142,111
V = $142,111 (or $142,100 when rounded)
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Exercise 6-2: Calculating a Multiplicative Model – Solution
Characteristics of the subject parcel:
Main living room 2,040 square feet
Finished basement 1,600 square feet
Unfinished basement 440 square feet
Garage 480 square feet
Fireplace 1
Quality grade 4
Effective age 15
Neighborhood 3
Use the model in Practical Application 6-2 to determine a value for the subject property.
Then:
EFFSQFT = 2,040 + (0.66 × 1,600) + (0.33 × 440) + (0.45 × 480) = 3,457
LINGRADE = 1.25
PCTGOOD = 1 - (15 ÷ 100) = 0.85
Value of subject parcel:
V = 59.49 × 34570.986 × 1.251.072 × 1.0521 × 0.850.680 × 1.1041
V = 59.49 × 3,084 × 1.27 × 1.052 × 0.895 × 1.104
V = $242,198 (or $242,200 when rounded)
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Exercise 6-3 Calculating a Hybrid Model – Solution
The subject parcel has the following characteristics:
Main living room 1,500 square feet
Finished basement 800 square feet
Unfinished basement 700 square feet
Garage 440 square feet
Quality grade 2
Effective age 30 years
Neighborhood 2
Lot size 7,200 square feet
Use the model given in Practical Application 6-3 to determine a value for the subject property.
Then:
LINGRADE = 0.80
PCTGOOD = 1 - (30 ÷100) = 0.70
Value of subject parcel:
V = 0.9331 × 1.1220 × [((.80.977 × 0.70.895) × (39.16 × 1,500) + (24.11 × 800) + (12.98 × 700))) +
(24.99 × 0) + (24.99 × 440) + (1.29 × 7,200))]
V = 0.933 × [(.5843 × (58,740 + 19,288 + 9,086)) + (10,996 + 9,288)]
V = 0.933 × ((.5843 × 87,114) + 20,284)
V = 0.933 × (50,901 + 20,284)
V = 0.933 × 71,185
V = $66,416 (or $66,400 when rounded)
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Exercise 6-4: Classification of Model Structure – Solution
1. Multiplicative
2. Hybrid
3. Additive
4. Hybrid
5. Multiplicative
6. Additive
7. Hybrid
8. Multiplicative
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Exercise 6-5: Measures of Goodness of Fit – Solution
1. 71.3 percent (as indicated by R-square)
2. COV = SEE ÷ Average value of Dependent Variable
3. $22.24 per square foot or 41.0%
4. Fair
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Exercise 6-6: Measures of Variable Importance – Solution
1. All the variables are significant at the 95% confidence level except LOTSIZE, PATIO, NBHD02, and
SITEAMEN.
2. An approximate 95 percent confidence interval for FIREPL can be computed as follows:
Lower 95% limit = 3402.099 - 2 × 654.902 = 2,092
Upper 95% limit = 3402.099 + 2 × 654.902 = 4,712
3. The three variables that have the greatest percentage impact on sale price, based on their beta values,
are SQFEET, QUAL, and NBHD05.
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1. No, it must first be converted to log format.
2. ln(SP)
3. ln(SQFT), ln(LINGRAD), ln(PCTGOOD), ln(LINHEAT), DOWNTOWN, CORNER
4. DOWNTOWN and CORNER
5. ex Where: e = base e
and x = 4.312
e4.312 or Exp (4.312) = 74.59
6. Yes (since b1 < 1.00)
7. Too much (since b3 < 1.00)
8. ex Where: e = base e
and x = 0.233
e.233 or Exp (.233) = 1.262
9. Yes (since b6 > 0)
10. SP = 74.59 × SQFT.977 × LINGRAD1.067 × PCTGOOD.751 × HEATING1.209 × 1.262DOWNTOWN ×
1.103CORNER
Exercise 6-7: Calibrating and Interpreting Multiplicative Models – Solution
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General qualitative = πGQ = 1.07
Building qualitative = πBQ = 1.08 × 1.12 = 1.2096
Building additive = ΣBA = (35.24 × 1,620) + (510 × 8) + (3,400 × 2) = 67,969
Land qualitative = πLQ = 1.15 × 1.00 = 1.15
Land additive = ΣLA = 1.43 × 9,000 = 12,870
Market value = πGQ × (πBQ × ΣBA + πLQ × ΣLA)
Market value = 1.07 × [(1.2096 × 67,969 + 1.15 × 12,870)] = $103,806
Building value = 1.07 × 1.2096 × 67,969 = $87,970
Land value = 1.07 × 1.15 × 12,870 = $15,836
Exercise 6-8: Estimating Value Using Feedback – Solution
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ATTRIBUTE SUBJECT
PROPERTY
SALE
PROPERTY DIFFERENCE
STANDARD
DEVIATION
Living area 1500 1660 -160 225.7
Age 8 4 4 4.1
Quality class 4 5 -1 0.9
ATTRIBUTE STANDARDIZED
DIFFERENCE
APPRAISER
ASSIGNED
WEIGHT
WEIGHTED
STD. DIFF.
SQUARED
WEIGHTED
STD. DIFF.
Living area -0.71 2 -1.42 2.02
Age 0.98 1 0.98 0.96
Quality class -1.11 1 -1.11 1.23
Sum 4.21
The metric value for this property is 4.21.
Exercise 6-9: Comparable Sales Algorithm – Solution
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REVIEW QUESTIONS – Chapter 6 SOLUTION
1. In mass appraisal, the sales comparison approach uses either the additive, multiplicative, or hybrid
model formats to arrive at final value estimates.
2. Multiple regression analysis (MRA) is a statistical technique for estimating unknown data based on
known and available data.
3. In regression statistics, the t-value is the ratio of a regression coefficient to its standard error (the
higher the ratio, the more significant the variable).
4. In an additive MRA model, bo represents the constant and X1 X2 ... XP represent the independent
variables.
5. The successful application of MRA models in mass appraisal require accurate property
characteristics data, adequate sales, good model building skills and variables to capture significant
location influences.
6. The regression statistic R-square is the percentage of the variation in sales price explained by the
model.
7. In regression statistics, the standard deviation of the regression error is termed the standard error of
estimate (SEE).
8. List three strengths and three limitations to feedback.
Strengths Limitations
Calibrates the generic model directly Lacks the rich diagnostics of MRA
Not overly affected by outliers Algorithms are proprietary and not
completely documented
Provides separate land and building values Software is relatively limited
9. Automated comparable sales provide a method of finding a given number of sales most comparable
to the subject parcel. It is based on a comparable sale algorithm. The user must be able to determine
the:
Sales to be searched
Variables used to define comparability
Relative weight given to each variable
10. The basic structure of the sales comparison model is V = Sc + ADJc.
11. An additive model structure for income properties in the sales comparison approach is V/UNIT = b0 +
(b1 × X1) + (b2 × X2) + (b3 × X3)...
12. In multiplicative models, in the sales comparison approach for income properties, sales prices are
converted to logarithms before calibration, making a per unit transformation unnecessary.
13. When calibrating an additive model, in the sales comparison approach for income properties, the
dependent variable is usually expressed on a per unit basis.
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14. List four requirements for effective MRA mass appraisal models.
Accurate property characteristics data
Location and proximity data
Adequate sales
Good modeling procedures
15. In regression statistics, the adjusted R-square adjusts for degrees of freedom providing an unbiased
estimate of R-square.
16. List five measures of variable importance that can be considered in regression analysis.
Coefficient of correlation
Correlation matrix
t-value
F-value
Beta-value
17. List five advantages of multiplicative MRA for income properties:
Captures interactive affects
Captures nonlinearities
Makes percentage adjustments
Taking logarithms reduces the span of the dependent variables
Retains the use of additive MRA for calibration purposes
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Chapter 7 | Income Approach
Exercise 7-1: Gross Rent Per Unit – Office Buildings – Solution
BLDG.
NO.
GROSS
RENT/S.F. MEDIAN
ABSOLUTE
DIFF. MEAN DIFF. DIFF. SQ.
2 $16.00 $19.50 $3.50 $19.30 $3.30 $10.89
6 $17.00 $19.50 $2.50 $19.30 $2.30 $5.29
5 $17.50 $19.50 $2.00 $19.30 $1.80 $3.24
1 $18.50 $19.50 $1.00 $19.30 $0.80 $0.64
3 $19.00 $19.50 $0.50 $19.30 $0.30 $0.09
10 $20.00 $19.50 $0.50 $19.30 $-0.70 $0.49
4 $20.50 $19.50 $1.00 $19.30 $-1.20 $1.44
8 $21.00 $19.50 $1.50 $19.30 $-1.70 $2.89
9 $21.50 $19.50 $2.00 $19.30 $-2.20 $4.84
7 $22.00 $19.50 $2.50 $19.30 $-2.70 $7.29
$193.00 $17.00 $37.10
The mean and median are very close. The median is the best choice since it is not influenced by the
extremes. The standard deviation shows about a $2.00 variation away from the mean. The COD indicates
an 8.72% variation from the median or about $1.70 per square foot. The reliability of the suggested gross
rent is good since the mean and median are close and all indications of variation are low.
Median $19.50 (19.00 + 20.00) ÷ 2
Mean $19.30 (193.00 ÷ 10)
Average Absolute Deviation $1.70 (17.00 ÷ 10)
Standard Deviation 2.03 Sqrt. of (37.10 ÷ 9)
Coefficient of Dispersion (COD) 8.72 (1.70 ÷ 19.50) × 100
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Exercise 7-2: Gross Rent Per Unit – Retail Store – Solution
Rents per square foot stratified by square foot area. (There is no consistent pattern relative to age.)
BLDG.
NO.
SQFT
AREA
RENT
PER SF
BLDG.
NO.
SQFT
AREA
RENT
PER SF
BLDG.
NO.
SQFT
AREA
RENT
PER SF
2 7,000 $16.00 1 11,200 $11.75 19 17,500 $7.75
6 7,700 $15.50 4 11,900 $11.50 3 18,200 $7.50
11 8,400 $15.00 13 12,600 $11.25 12 19,600 $7.25
15 9,100 $15.00 7 13,300 $11.00 18 20,300 $7.00
17 9,800 $14.75 16 14,000 $10.75 5 21,000 $6.75
8 10,500 $14.25 10 15,400 $10.50 14 22,400 $6.50
20 16,100 $10.25 9 23,800 $6.25
Median 15.00 Median 11.00 Median 7.00
Mean 15.08 Mean 11.00 Mean 7.00
Standard deviation 0.61 Standard deviation 0.54 Standard deviation 0.548
Typical gross rent $15.00 sqft Typical
gross rent $11.00 sqft
Typical
gross rent $7.00 sqft
In each case, the mean and median are the same or very close, indicating no outliers. In addition, the
standard deviation indicates a variation of just over $0.50 for two-thirds of the rents. Therefore, the
stratification by size has produced a reliable indicator of the typical rent per square foot.
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Exercise 7-3: Developing Gross Income Multipliers (GIMs) – Solution
Properties Arrayed by GIM
SALE
NO.
SALE
PRICE
GROSS
INCOME
EFF AGE
GIM
MEDIAN
ABS DEV
12 $280,000 $48,700 35 5.75 7.13 1.38
11 $264,000 $44,000 34 6.00 7.13 1.13
9 $372,000 $59,520 34 6.25 7.13 0.88
4 $320,000 $49,230 32 6.50 7.13 0.63
2 $272,000 $40,300 32 6.75 7.13 0.38
1 $256,000 $36,550 25 7.00 7.13 0.13
7 $432,000 $59,590 24 7.25 7.13 0.12
5 $336,000 $44,800 22 7.50 7.13 0.37
3 $360,000 $46,450 20 7.75 7.13 0.62
6 $304,000 $38,000 13 8.00 7.13 0.87
8 $248,000 $29,180 12 8.50 7.13 1.37
10 $310,000 $35,430 10 8.75 7.13 1.62
9.50
Median 7. 13
Mean 7.17
COD 11.11 (9.50 ÷ 12 = 0.792) (0.792 ÷ 7.13 × 100 = 11.11)
Although the mean and median are very close, there is a greater than 10% spread as indicated by the
COD. Stratifying the GIMs by age groups (10 to 19, 20 to 29, and 30 to 39) would produce the following:
GROUP 1
30–39
GROUP 2
20–29
GROUP 3
10–19
Mean 6.25 7.38 8.42
Median 6.50 7.38 8.50
COD 4.80 3.39 2.94
In each case, the mean and median remain the same or close. However, the COD has dropped
significantly. Therefore, there is a greater amount of reliability in the GIM, if it is selected based on this age
grouping.
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Exercise 7-4: Interpreting a GIM Model – Solution
1. 4.815 + 0.566 + 0.442 – (Sq. root of 20,000) × 0.004673)
4.815 + 0.566 + 0.442 – 0.661 = 5.162
2. Area 04
3. Decrease (as indicated by the negative coefficient for SQRSIZE)
4. 2 × 0.566 = 1.132
5. AGE did not enter the model because the condition variables (COND-GD and COND-PR) account
for effective age.
6. 65.97% (R-Square)
7. 100 × (.83961 ÷ 4.975) = 16.9
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Exercise 7-5: Expense Ratio Analysis – Solution
Apartment Buildings
CMPLEX
NO
AGE
EXP RATIO
ARRAYED
CMPLEX
NO
AGE
EXP RATIO
ARRAYED
84 25 20.5 44 39 38.0
34 20 35.0 140 31 42.1
312 21 35.5 38 37 43.2
20 23 36.0 91 31 44.4
66 24 36.3 65 34 45.3
122 29 38.2 85 32 46.0
72 23 42.5 75 36 65.0
Median 36.0 Median 44.4
Mean 34.8 Mean 46.3
Trimmed mean 36.2 Trimmed mean 44.2
Standard dev: 6.83 Standard dev: 8.67
Standard dev:
(Trimmed mean)
1.22
Standard dev:
(Trimmed mean)
1.57
CMPLEX
NO
AGE
EXP RATIO
ARRAYED
19 45 38.5 Median 52.0
300 47 50.0 Mean 53.9
89 42 51.2 Trimmed mean 52.4
37 41 52.0 Standard dev: 11.37
130 48 53.5 Standard dev:
(Trimmed mean)
2.06
95 43 55.3
71 47 76.5
Excluding the outliers provides a mean that is close to the median. In addition, the standard deviation
drops significantly with the elimination of the outliers. This ensures the reliability of the estimated typical
expense ratio.
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Exercise 7-6: Retail Expense Ratio Model – Solution
1. A fair grade retail store with an effective age of 10 years, in REGION 1 has an expense ratio of
47% .
0.333099 + (-1 × -0.045630) + (10 × 0.002952) + 0.058028 = 0.466277
2. A very good grade retail store with an effective age of 3 years, in REGION 6 has an expense ratio
of 23% .
0.333099 + (2 × -0.045630) + (3 × 0.002952) - 0.023731 = 0.226964
3. An average grade retail store with an effective age of 12 years, in REGION 4 has an expense ratio
of 37% .
0.333099 + (0 × -0.045630) + (12 × 0.002952) = 0.368523
4. Which location variable has the lowest significance? REGION4
5. Which location variable is used as the reference location variable? REGION3
6. The coefficient of variation for the model is 7.48% .
0.02639 ÷ 0.35270 = 0.0748228 × 100 = 7.48228
7. What is the confidence level for the REGION5 variable? 98%
1 - 0.0197 = 0.9803
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Exercise 7-7: Calculating a Vacancy Ratio – Solution
Eight centers arrayed by vacancy ratio:
PARCEL NUMBER
SQUARE FEET
NET LEASABLE
AREA
SQUARE FEET
CURRENT VACANT
AREA
VACANCY
RATES
4632-193-05-122 95,000 2,850 0.030
4632-061-01-072 86,000 3,440 0.040
4632-262-28-012 86,000 3,870 0.045
4632-124-02-013 88,000 4,225 0.048
4632-291-12-112 85,000 4,420 0.052
4632-082-18-030 90,000 4,950 0.055
4632-144-14-056 92,000 5,520 0.060
4632-301-10-090 91,000 13,650 0.150
Minimum 0.030
Maximum 0.150
Range 0.120
Median 0.050
Mean 0.060
Trimmed mean 0.050
Selected vacancy ratio 0.050
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Exercise 7-8: Evaluating OARs – Solution
1. The following do not fit the expected pattern:
a) Class A building in declining areas (only 2 sales)
b) Class B building in appreciating areas (4 sales)
2. OARs for these two strata could be changed to numbers that fall in the following ranges:
a) 0.150–0.160
b) 0.135–0.140
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Exercise 7-9: Example of OAR Model – Solution
1. (0.02031 ÷ 0.1033) × 100 = 19.7
2. -0.020 to +0.020
3. LINGRADE, CONVERSN, NBHD102
4. EFFAGE, NBHD105, SQRUNITS
5. OAR = 0.09980 + 0.00039 × 15 - 0.00571 + 0.00117 × 8 = 0.109
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REVIEW QUESTIONS – Chapter 7 SOLUTION
1. When estimating market rents either potential or effective gross income is used.
2. One of the characteristics by which properties are grouped is location.
3. One of the modeling considerations for gross income models is that the dependent variable is on a
per unit basis.
4. The two basic methods of developing GIMs are stratification and multiple regression.
5. GIM = sale price divided by gross income.
6. The reliability of GIMs developed through stratification is evaluated by examining:
Sample size
Measures of dispersion
Consistency among strata
7. The two basic methods for developing per unit rents, expense ratios, GIMs, and OARs are
stratification and multiple regression.
8. OAR = net income divided by sale price (value).
9. Potential gross income less vacancy and collection losses equals effective gross income.
10. The dependent variable in the gross income model is gross income per unit.
11. The dependent variable in a GIM model is sale price/gross income.
12. The dependent variable in an OAR model is net income/sale price.
13. The measure of goodness-of-fit that is used in direct sale price models but is less useful in income
models is R-square.
14. Vacancy and collection losses reflect typical management.
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15. Consider the following ten expense ratios:
0.112 0.375
0.156 0.401
0.231 0.455
0.277 0.570
0.327 0.732
A. Compute the median and trimmed mean ignoring the two lowest and two highest values.
Median: (0.327 + 0.375) ÷ 2 = 0.351
Trimmed mean: (0.231 + 0.277 + 0.327 + 0.375 + 0.401 + 0.455) ÷ 6 = 0.34
B. Calculate the COD of the 10 ratios.
Ratio Abs Dev
0.112 0.239
0.156 0.195
0.231 0.120
0.277 0.074
0.327 0.024
0.375 0.024
0.401 0.050
0.455 0.104
0.570 0.219
0.732 0.381
______
Sum 1.430
COD = 100 × (1.430 ÷ 10) / 0.351 = 40.7
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C. Calculate the standard deviation and COV about the trimmed mean (ignoring the two highest and
lowest values).
Ratio Dev from Trimmed
Mean
Dev
Squared
0.231 -0.113 0.0128
0.277 -0.067 0.0045
0.327 -0.017 0.0003
0.375 0.031 0.0010
0.401 0.057 0.0032
0.455 0.111 0.0123
Sum 0.341
STD DEV = SQRT (0.0341 ÷ 5) = 0.0825
COV = 100 × (0.0825 ÷ 0.344) = 24.0
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Chapter 8 – Solutions Set 91
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Chapter 8 | Value Review and Maintenance
Exercise 8–1: Interpretation of Sales Ratio Results – Solution
Neighborhoods 500 and 501:
• Within an acceptable range; do not require further attention.
Neighborhood 502:
• The median is below the acceptable range. In addition, the PRD of 1.07 indicates an under
valuation of higher value properties.
• If the cost approach was used, this may indicate a problem with the depreciation table.
• If the sales comparison approach was used, this may indicate a problem with the sales model or
the sales base used to develop the values.
Neighborhood 503:
• Shows a median that is outside the range. The COD is acceptable; therefore, this neighborhood
could be trended.
Neighborhood 504:
• There is a problem with both the median and the COD. In addition, the PRD of 1.04 suggests that
there may be a slight bias toward high value properties. A field review is necessary for this
neighborhood to ensure correct physical characteristics are in the database.
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Chapter 8 – Solutions Set 93
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REVIEW QUESTIONS – Chapter 8 SOLUTION
1. Pilot studies are used when implementing a new CAMA system or valuation techniques, because
they provide a test on a sample or test area.
2. Once preliminary values are produced, an office review is an essential first step in quality control.
3. Sales ratio studies are one of the best tools to measure the quality of new appraised values during
the review process.
4. List three items that are required for an effective field review.
Assessment maps
Property record cards
Valuation reports
5. List three aspects of value acceptability.
Accuracy
Stability
Explainability
6. Two goodness-of-fit statistics used to evaluate accuracy when using multiple regression are:
R-square
Standard error of estimate
7. List three steps that are used to promote a greater understanding of multiple regression
other than conversion to the base home approach.
Simplified models
Stepwise MRA
Constrained MRA
8. List four update strategies that are typically used by an assessor’s office.
Full recalibration
Cyclical recalibration with interim adjustments
Partial recalibration
Use of previous year’s values
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Quiz 2 – Solutions Set 95
© 2020 International Association of Assessing Officers
Quiz 2 Solutions
1. V = bo + '(b1 * Xl) + (b2 * X2) + (b3 * X3) ... is an example of a/an model structure for
the sales comparison approach.
A. Additive
B. Hybrid
C. Multiplicative
D. Adaptive Estimation
2. Consider the following regression statistics:
N=349
Adjusted R-Square = .879
Standard Error of Estimate (SEE) = 9800
Average sale price = $100,000
On a percentage basis, approximately two-thirds of the regression errors would fall
within what range:
A. -9.8% to +9.8%
B. -12.1% to +12.1%
C. -19.6% to +19.6%
D. 0% to 12.1%
3. In regression statistics, the most accurate measure of the percentage of variation in
sales prices explained by the model is the
A. R-square
B. Adjusted R-square
C. Standard Error of Estimate (SEE)
D. Coefficient of variation
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4. In regression statistics, the ____________________ is the ratio of a regression
coefficient to its standard error (the higher the ratio, the more significant the
variable).
A. R-square
B. Adjusted R-square
C. Standard Error of Estimate (SEE)
D. t-value
5. In multiple regression analysis, _______________ represents the difference between
actual and predicted sales prices.
A. Standard error of estimate
B. Coefficient of variation
C. Residuals
D. None of the above
6. Which of the following employs the Euclidean distance metric:
A. Automated comparable sales
B. Location value response surface analysis
C. Adaptive estimation procedure
D. Multiplicative MRA
7. During the office review of values, the reasonableness, consistency and credibility of
values can be gauged through:
A. Ratio studies
B. Benchmark values
C. Average change in values
D. All of the above
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8. Materials required for an effective field review of values include:
A. Assessment maps and property record cards
B. Sales ratio reports
C. Average value change reports
D. All of the above
9. Aspects of value acceptability are:
A. Accuracy
B. Stability
C. Explainability
D. All of the above
10. Which of the following maximizes accuracy versus stability?
A. Full recalibration
B. Cyclical recalibration with interim adjustments
C. Partial recalibration
D. All of the above
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11. In mass appraisal, multiple regression analysis (MRA) works on the principle of:
A. Passing the sales file multiple times until the process stabilizes and the
coefficients converge on their "optimal" values
B. Minimizing the sum of the absolute errors between actual sales prices and
predicted prices
C. Minimizing the squared errors between actual and predicted sales prices
D. Finding the best comparables through a predefined metric (e.g., Euclidean
distance metric) and adjusting the comparables to the subject
12. The ________________________ model is the most flexible model structure; however, it
is the most difficult to calibrate.
A. Additive model
B. Multiplicative model
C. Hybrid model
D. None of the above
13. When modeling income properties, sample sizes can best be expanded by:
A. Extending the period from which sales are drawn
B. Combining property types
C. Using non-market sales
D. Supplementing sales with prior year values
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14. Which of the following is the most appropriate calibration tool for a multiplicative
model?
A. Additive MRA
B. Feedback
C. Nonlinear MRA
D. Loglinear MRA
15. Which of the following measures the significance of independent variables in the
regression model?
A. Correlation coefficient
B. t-value
C. Adjusted R square
D. Standard Error of Estimate
16. Consider the following model:
SP/SQFT = 61.85 * SQFT.977 * PCTGOOD.652
Which of the following is true?
A. The model is hybrid in form.
B. The contribution of SQFT to value is linear.
C. The model is multiplicative in form.
D. The effect of SQFT and PCTGOOD upon value is additive.
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17. Consider the following indicated gross income multipliers:
Sales Median COD
GIM
Superior Economic Area
Newer Apartments 9 6.5 10.1
Mid-Age Apartments 5 6.3 12.4
Older Apartments 3 6.0 15.6
Average Economic Area
Newer Apartments 4 6.7 17.4
Mid-Age Apartments 11 5.9 14.1
Older Apartments 2 5.4 23.6
Which of the multipliers is inconsistent with prior expectations based on appraisal
theory and thus most likely to require override?
A. The multiplier of 6.0 for older apartments in the superior economic area
B. The multiplier of 6.7 for newer apartments in the average economic area
C. The multiplier of 5.9 for mid-age apartments in the average economic area
D. The multiplier of 5.4 for older apartments in the average economic area
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18. In developing gross income models for a large metropolitan area, it would be most
important to stratify properties by:
A. Economic area
B. Size, stories, or number of units
C. Value
D. Use class
19. Which of the following is least effective in evaluating the reliability of an expense
ratio model?
A. R-square
B. Standard Error of Estimate
C. Coefficient of variation
D. Coefficient of dispersion
20. Which of the following is an important component of the field review of values?
A. Assessment maps
B. Property record cards
C. Valuation reports
D. All of the above
21. Cyclical recalibration with interim adjustments:
A. Tends to maximize accuracy
B. Tends to maximize stability
C. Sacrifices stability
D. Maintains reasonable accuracy while emphasizing stability
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22. What would be the value of an office building with 2,500 square feet using the
following income model? Round to the nearest hundred dollars.
Rent $15.00/sf
Vacancy & collection loss 5%
Expenses 15%
Miscellaneous income 2%
Capitalization Rate 8%
A. $370,900
B. $378,500
C. $386,500
D. $398,400
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Solutions Set
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