The Comparable Selections Table allows user build/edit/choose an existing Selection Model for the Residential Appraisal Sales Comparison.
User must use BOTH the Comparable Selection Table and the Comparable Adjustments Table in order to produce a Comparable Sales Value in the Base Values Tab.
From the Appraisal File go to:
Tables — Appraisal Tables — Comparable Selection
Comparable Selection model tells LandMark what components determine comparability.
Model Info
Selection ID: System generated
Selection Code: Model code name
Description: Description of model
Model Type: Minkowski
The IAAO has two different methodologies for calculating distance metrics: Minkowski and Euclidean.
- Minkowski is simpler and quicker to calculate. (This is the one LandMark uses.)
- Euclidean is more complicated, takes longer to calculate and will standardize and make adjustments for the differences found.
Maximum Sales: How many sales user wants system to generate based on given variables.
The fewer sales user includes, the more impact an outlier can have. Six to ten is a good sales range, but this will vary greatly from county to county.
Date Range: Date range of recent sales.
UPDATE Date Range for Comparables in the Sale Selections Table to include the new year before setting values.
Selection Options
Use of Subjects Neighborhood: Check box to use subject’s neighborhood.
Neighborhood Range: Range of comparable neighborhoods
Please Note: In LandMark we want Neighborhoods to be true, market-based areas. (These are not multipliers.) Neighborhoods can have their own model or can share models.
Include Subject as Comparable This is appraiser preference.
Exclude Duplicate Accounts: Checking this box would keep the system from using the same property, yet different sales as multiple comparables.
Max Calc Distance: THIS IS NOT PHYSICAL DISTANCE. THE IAAO HAS A DISTANCE METRICS BASED ON COMPARIBILTY INDEXES. (see Minkowski model type above)
- The Distance metric range is 0-140 (0—completely comparable, 140—completely dissimilar), between 10-20 is a good place to start.
- If the model isn’t yielding enough comparables, user may widen the distance.
- User may want to use a lower distance if comparables are abundant (ie. a subdivision with lots of sales).
Example: If year built, area, quality, neighborhood, and exterior wall are the same in two comparables, then you have max calculated distance of 0 (zero).
Max Physical Distance: maximum miles for comparable to be from subject.
In order to calculate this, the Geo Location MUST be filed in the Assessment file on Name/Situs (2nd tab). See Update Lat/Long. The whole county or whole neighborhood must have the Geo Location filed in to use it.
Selection Variables
Selection Variables are the weighted variables an appraiser considers in comparables to build an algorithm. These models can be published and shared between counties.
Sequence: System generated order number.
Source Field: Field name to compare/consider from Residential Data (4th tab) Appraisal File. These must be in brackets and match the field name in case and form.
Example: Quality [Quality] or Exterior Wall [Ext Wall]
Equation: Must be in brackets and match case and form.
Weight: The percentage of weight the appraiser wants to give each variable.
Feedback
Post your comment on this topic.