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https://ww2.amstat.org/publications/jse/v19n3/decock.pdf

NAME: AmesHousing.txt TYPE: Population SIZE: 2930 observations, 82 variables ARTICLE TITLE: Ames Iowa: Alternative to the Boston Housing Data Set

DESCRIPTIVE ABSTRACT: Data set contains information from the Ames Assessor’s Office used in computing assessed values for individual residential properties sold in Ames, IA from 2006 to 2010.

SOURCES: Ames, Iowa Assessor’s Office

VARIABLE DESCRIPTIONS: Tab characters are used to separate variables in the data file. The data has 82 columns which include 23 nominal, 23 ordinal, 14 discrete, and 20 continuous variables (and 2 additional observation identifiers).

Order (Discrete): Observation number

PID (Nominal): Parcel identification number - can be used with city web site for parcel review.

MS SubClass (Nominal): Identifies the type of dwelling involved in the sale.

   020	1-STORY 1946 & NEWER ALL STYLES
   030	1-STORY 1945 & OLDER
   040	1-STORY W/FINISHED ATTIC ALL AGES
   045	1-1/2 STORY - UNFINISHED ALL AGES
   050	1-1/2 STORY FINISHED ALL AGES
   060	2-STORY 1946 & NEWER
   070	2-STORY 1945 & OLDER
   075	2-1/2 STORY ALL AGES
   080	SPLIT OR MULTI-LEVEL
   085	SPLIT FOYER
   090	DUPLEX - ALL STYLES AND AGES
   120	1-STORY PUD (Planned Unit Development) - 1946 & NEWER
   150	1-1/2 STORY PUD - ALL AGES
   160	2-STORY PUD - 1946 & NEWER
   180	PUD - MULTILEVEL - INCL SPLIT LEV/FOYER
   190	2 FAMILY CONVERSION - ALL STYLES AND AGES

MS Zoning (Nominal): Identifies the general zoning classification of the sale.

   A	Agriculture
   C	Commercial
   FV	Floating Village Residential
   I	Industrial
   RH	Residential High Density
   RL	Residential Low Density
   RP	Residential Low Density Park 
   RM	Residential Medium Density

Lot Frontage (Continuous): Linear feet of street connected to property

Lot Area (Continuous): Lot size in square feet

Street (Nominal): Type of road access to property

   Grvl	Gravel	
   Pave	Paved

Alley (Nominal): Type of alley access to property

   Grvl	Gravel
   Pave	Paved
   NA 	No alley access

Lot Shape (Ordinal): General shape of property

   Reg	Regular	
   IR1	Slightly irregular
   IR2	Moderately Irregular
   IR3	Irregular

Land Contour (Nominal): Flatness of the property

   Lvl	Near Flat/Level	
   Bnk	Banked - Quick and significant rise from street grade to building
   HLS	Hillside - Significant slope from side to side
   Low	Depression

Utilities (Ordinal): Type of utilities available

   AllPub	All public Utilities (E,G,W,& S)	
   NoSewr	Electricity, Gas, and Water (Septic Tank)
   NoSeWa	Electricity and Gas Only
   ELO	Electricity only	

Lot Config (Nominal): Lot configuration

   Inside	Inside lot
   Corner	Corner lot
   CulDSac	Cul-de-sac
   FR2	Frontage on 2 sides of property
   FR3	Frontage on 3 sides of property

Land Slope (Ordinal): Slope of property

   Gtl	Gentle slope
   Mod	Moderate Slope	
   Sev	Severe Slope

Neighborhood (Nominal): Physical locations within Ames city limits (map available)

   Blmngtn	Bloomington Heights
   Blueste	Bluestem
   BrDale	Briardale
   BrkSide	Brookside
   ClearCr	Clear Creek
   CollgCr	College Creek
   Crawfor	Crawford
   Edwards	Edwards
   Gilbert	Gilbert
   Greens	Greens
   GrnHill	Green Hills
   IDOTRR	Iowa DOT and Rail Road
   Landmrk	Landmark
   MeadowV	Meadow Village
   Mitchel	Mitchell
   Names	North Ames
   NoRidge	Northridge
   NPkVill	Northpark Villa
   NridgHt	Northridge Heights
   NWAmes	Northwest Ames
   OldTown	Old Town
   SWISU	South & West of Iowa State University
   Sawyer	Sawyer
   SawyerW	Sawyer West
   Somerst	Somerset
   StoneBr	Stone Brook
   Timber	Timberland
   Veenker	Veenker

Condition 1 (Nominal): Proximity to various conditions

   Artery	Adjacent to arterial street
   Feedr	Adjacent to feeder street	
   Norm	Normal	
   RRNn	Within 200' of North-South Railroad
   RRAn	Adjacent to North-South Railroad
   PosN	Near positive off-site feature--park, greenbelt, etc.
   PosA	Adjacent to postive off-site feature
   RRNe	Within 200' of East-West Railroad
   RRAe	Adjacent to East-West Railroad

Condition 2 (Nominal): Proximity to various conditions (if more than one is present)

   Artery	Adjacent to arterial street
   Feedr	Adjacent to feeder street	
   Norm	Normal	
   RRNn	Within 200' of North-South Railroad
   RRAn	Adjacent to North-South Railroad
   PosN	Near positive off-site feature--park, greenbelt, etc.
   PosA	Adjacent to postive off-site feature
   RRNe	Within 200' of East-West Railroad
   RRAe	Adjacent to East-West Railroad

Bldg Type (Nominal): Type of dwelling

   1Fam	Single-family Detached	
   2FmCon	Two-family Conversion; originally built as one-family dwelling
   Duplx	Duplex
   TwnhsE	Townhouse End Unit
   TwnhsI	Townhouse Inside Unit

House Style (Nominal): Style of dwelling

   1Story	One story
   1.5Fin	One and one-half story: 2nd level finished
   1.5Unf	One and one-half story: 2nd level unfinished
   2Story	Two story
   2.5Fin	Two and one-half story: 2nd level finished
   2.5Unf	Two and one-half story: 2nd level unfinished
   SFoyer	Split Foyer
   SLvl	Split Level

Overall Qual (Ordinal): Rates the overall material and finish of the house

   10	Very Excellent
   9	Excellent
   8	Very Good
   7	Good
   6	Above Average
   5	Average
   4	Below Average
   3	Fair
   2	Poor
   1	Very Poor

Overall Cond (Ordinal): Rates the overall condition of the house

   10	Very Excellent
   9	Excellent
   8	Very Good
   7	Good
   6	Above Average	
   5	Average
   4	Below Average	
   3	Fair
   2	Poor
   1	Very Poor

Year Built (Discrete): Original construction date

Year Remod/Add (Discrete): Remodel date (same as construction date if no remodeling or additions)

Roof Style (Nominal): Type of roof

   Flat	Flat
   Gable	Gable
   Gambrel	Gabrel (Barn)
   Hip	Hip
   Mansard	Mansard
   Shed	Shed

Roof Matl (Nominal): Roof material

   ClyTile	Clay or Tile
   CompShg	Standard (Composite) Shingle
   Membran	Membrane
   Metal	Metal
   Roll	Roll
   Tar&Grv	Gravel & Tar
   WdShake	Wood Shakes
   WdShngl	Wood Shingles

Exterior 1 (Nominal): Exterior covering on house

   AsbShng	Asbestos Shingles
   AsphShn	Asphalt Shingles
   BrkComm	Brick Common
   BrkFace	Brick Face
   CBlock	Cinder Block
   CemntBd	Cement Board
   HdBoard	Hard Board
   ImStucc	Imitation Stucco
   MetalSd	Metal Siding
   Other	Other
   Plywood	Plywood
   PreCast	PreCast	
   Stone	Stone
   Stucco	Stucco
   VinylSd	Vinyl Siding
   Wd Sdng	Wood Siding
   WdShing	Wood Shingles

Exterior 2 (Nominal): Exterior covering on house (if more than one material)

   AsbShng	Asbestos Shingles
   AsphShn	Asphalt Shingles
   BrkComm	Brick Common
   BrkFace	Brick Face
   CBlock	Cinder Block
   CemntBd	Cement Board
   HdBoard	Hard Board
   ImStucc	Imitation Stucco
   MetalSd	Metal Siding
   Other	Other
   Plywood	Plywood
   PreCast	PreCast
   Stone	Stone
   Stucco	Stucco
   VinylSd	Vinyl Siding
   Wd Sdng	Wood Siding
   WdShing	Wood Shingles

Mas Vnr Type (Nominal): Masonry veneer type

   BrkCmn	Brick Common
   BrkFace	Brick Face
   CBlock	Cinder Block
   None	None
   Stone	Stone

Mas Vnr Area (Continuous): Masonry veneer area in square feet

Exter Qual (Ordinal): Evaluates the quality of the material on the exterior

   Ex	Excellent
   Gd	Good
   TA	Average/Typical
   Fa	Fair
   Po	Poor

Exter Cond (Ordinal): Evaluates the present condition of the material on the exterior

   Ex	Excellent
   Gd	Good
   TA	Average/Typical
   Fa	Fair
   Po	Poor

Foundation (Nominal): Type of foundation

   BrkTil	Brick & Tile
   CBlock	Cinder Block
   PConc	Poured Contrete	
   Slab	Slab
   Stone	Stone
   Wood	Wood

Bsmt Qual (Ordinal): Evaluates the height of the basement

   Ex	Excellent (100+ inches)	
   Gd	Good (90-99 inches)
   TA	Typical (80-89 inches)
   Fa	Fair (70-79 inches)
   Po	Poor (<70 inches
   NA	No Basement

Bsmt Cond (Ordinal): Evaluates the general condition of the basement

   Ex	Excellent
   Gd	Good
   TA	Typical - slight dampness allowed
   Fa	Fair - dampness or some cracking or settling
   Po	Poor - Severe cracking, settling, or wetness
   NA	No Basement

Bsmt Exposure (Ordinal): Refers to walkout or garden level walls

   Gd	Good Exposure
   Av	Average Exposure (split levels or foyers typically score average or above)	
   Mn	Mimimum Exposure
   No	No Exposure
   NA	No Basement

BsmtFin Type 1 (Ordinal): Rating of basement finished area

   GLQ	Good Living Quarters
   ALQ	Average Living Quarters
   BLQ	Below Average Living Quarters	
   Rec	Average Rec Room
   LwQ	Low Quality
   Unf	Unfinshed
   NA	No Basement

BsmtFin SF 1 (Continuous): Type 1 finished square feet

BsmtFinType 2 (Ordinal): Rating of basement finished area (if multiple types)

   GLQ	Good Living Quarters
   ALQ	Average Living Quarters
   BLQ	Below Average Living Quarters	
   Rec	Average Rec Room
   LwQ	Low Quality
   Unf	Unfinshed
   NA	No Basement

BsmtFin SF 2 (Continuous): Type 2 finished square feet

Bsmt Unf SF (Continuous): Unfinished square feet of basement area

Total Bsmt SF (Continuous): Total square feet of basement area

Heating (Nominal): Type of heating

   Floor	Floor Furnace
   GasA	Gas forced warm air furnace
   GasW	Gas hot water or steam heat
   Grav	Gravity furnace	
   OthW	Hot water or steam heat other than gas
   Wall	Wall furnace

HeatingQC (Ordinal): Heating quality and condition

   Ex	Excellent
   Gd	Good
   TA	Average/Typical
   Fa	Fair
   Po	Poor

Central Air (Nominal): Central air conditioning

   N	No
   Y	Yes

Electrical (Ordinal): Electrical system

   SBrkr	Standard Circuit Breakers & Romex
   FuseA	Fuse Box over 60 AMP and all Romex wiring (Average)	
   FuseF	60 AMP Fuse Box and mostly Romex wiring (Fair)
   FuseP	60 AMP Fuse Box and mostly knob & tube wiring (poor)
   Mix	Mixed

1st Flr SF (Continuous): First Floor square feet

2nd Flr SF (Continuous) : Second floor square feet

Low Qual Fin SF (Continuous): Low quality finished square feet (all floors)

Gr Liv Area (Continuous): Above grade (ground) living area square feet

Bsmt Full Bath (Discrete): Basement full bathrooms

Bsmt Half Bath (Discrete): Basement half bathrooms

Full Bath (Discrete): Full bathrooms above grade

Half Bath (Discrete): Half baths above grade

Bedroom (Discrete): Bedrooms above grade (does NOT include basement bedrooms)

Kitchen (Discrete): Kitchens above grade

KitchenQual (Ordinal): Kitchen quality

   Ex	Excellent
   Gd	Good
   TA	Typical/Average
   Fa	Fair
   Po	Poor

TotRmsAbvGrd (Discrete): Total rooms above grade (does not include bathrooms)

Functional (Ordinal): Home functionality (Assume typical unless deductions are warranted)

   Typ	Typical Functionality
   Min1	Minor Deductions 1
   Min2	Minor Deductions 2
   Mod	Moderate Deductions
   Maj1	Major Deductions 1
   Maj2	Major Deductions 2
   Sev	Severely Damaged
   Sal	Salvage only

Fireplaces (Discrete): Number of fireplaces

FireplaceQu (Ordinal): Fireplace quality

   Ex	Excellent - Exceptional Masonry Fireplace
   Gd	Good - Masonry Fireplace in main level
   TA	Average - Prefabricated Fireplace in main living area or Masonry Fireplace in basement
   Fa	Fair - Prefabricated Fireplace in basement
   Po	Poor - Ben Franklin Stove
   NA	No Fireplace

Garage Type (Nominal): Garage location

   2Types	More than one type of garage
   Attchd	Attached to home
   Basment	Basement Garage
   BuiltIn	Built-In (Garage part of house - typically has room above garage)
   CarPort	Car Port
   Detchd	Detached from home
   NA	No Garage

Garage Yr Blt (Discrete): Year garage was built

Garage Finish (Ordinal) : Interior finish of the garage

   Fin	Finished
   RFn	Rough Finished	
   Unf	Unfinished
   NA	No Garage

Garage Cars (Discrete): Size of garage in car capacity

Garage Area (Continuous): Size of garage in square feet

Garage Qual (Ordinal): Garage quality

   Ex	Excellent
   Gd	Good
   TA	Typical/Average
   Fa	Fair
   Po	Poor
   NA	No Garage

Garage Cond (Ordinal): Garage condition

   Ex	Excellent
   Gd	Good
   TA	Typical/Average
   Fa	Fair
   Po	Poor
   NA	No Garage

Paved Drive (Ordinal): Paved driveway

   Y	Paved 
   P	Partial Pavement
   N	Dirt/Gravel

Wood Deck SF (Continuous): Wood deck area in square feet

Open Porch SF (Continuous): Open porch area in square feet

Enclosed Porch (Continuous): Enclosed porch area in square feet

3-Ssn Porch (Continuous): Three season porch area in square feet

Screen Porch (Continuous): Screen porch area in square feet

Pool Area (Continuous): Pool area in square feet

Pool QC (Ordinal): Pool quality

   Ex	Excellent
   Gd	Good
   TA	Average/Typical
   Fa	Fair
   NA	No Pool

Fence (Ordinal): Fence quality

   GdPrv	Good Privacy
   MnPrv	Minimum Privacy
   GdWo	Good Wood
   MnWw	Minimum Wood/Wire
   NA	No Fence

Misc Feature (Nominal): Miscellaneous feature not covered in other categories

   Elev	Elevator
   Gar2	2nd Garage (if not described in garage section)
   Othr	Other
   Shed	Shed (over 100 SF)
   TenC	Tennis Court
   NA	None

Misc Val (Continuous): $Value of miscellaneous feature

Mo Sold (Discrete): Month Sold (MM)

Yr Sold (Discrete): Year Sold (YYYY)

Sale Type (Nominal): Type of sale

   WD 	Warranty Deed - Conventional
   CWD	Warranty Deed - Cash
   VWD	Warranty Deed - VA Loan
   New	Home just constructed and sold
   COD	Court Officer Deed/Estate
   Con	Contract 15% Down payment regular terms
   ConLw	Contract Low Down payment and low interest
   ConLI	Contract Low Interest
   ConLD	Contract Low Down
   Oth	Other

Sale Condition (Nominal): Condition of sale

   Normal	Normal Sale
   Abnorml	Abnormal Sale -  trade, foreclosure, short sale
   AdjLand	Adjoining Land Purchase
   Alloca	Allocation - two linked properties with separate deeds, typically condo with a garage unit	
   Family	Sale between family members
   Partial	Home was not completed when last assessed (associated with New Homes)

SalePrice (Continuous): Sale price $$

SPECIAL NOTES: There are 5 observations that an instructor may wish to remove from the data set before giving it to students (a plot of SALE PRICE versus GR LIV AREA will indicate them quickly). Three of them are true outliers (Partial Sales that likely don’t represent actual market values) and two of them are simply unusual sales (very large houses priced relatively appropriately). I would recommend removing any houses with more than 4000 square feet from the data set (which eliminates these 5 unusual observations) before assigning it to students.

STORY BEHIND THE DATA: This data set was constructed for the purpose of an end of semester project for an undergraduate regression course. The original data (obtained directly from the Ames Assessor’s Office) is used for tax assessment purposes but lends itself directly to the prediction of home selling prices. The type of information contained in the data is similar to what a typical home buyer would want to know before making a purchase and students should find most variables straightforward and understandable.

PEDAGOGICAL NOTES: Instructors unfamiliar with multiple regression may wish to use this data set in conjunction with an earlier JSE paper that reviews most of the major issues found in regression modeling:

Kuiper , S. (2008), “Introduction to Multiple Regression: How Much Is Your Car Worth?”, Journal of Statistics Education Volume 16, Number 3 (2008).

Outside of the general issues associated with multiple regression discussed in this article, this particular data set offers several opportunities to discuss how the purpose of a model might affect the type of modeling done. User of this data may also want to review another JSE article related directly to real estate pricing:

Pardoe , I. (2008), “Modeling home prices using realtor data”, Journal of Statistics Education Volume 16, Number 2 (2008).

One issue is in regards to homoscedasticity and assumption violations. The graph included in the article appears to indicate heteroscedasticity with variation increasing with sale price and this problem is evident in many simple home pricing models that focus only on house and lot sizes. Though this violation can be alleviated by transforming the response variable (sale price), the resulting equation yields difficult to interpret fitted values (selling price in log or square root dollars). This situation gives the instructor the opportunity to talk about the costs (biased estimators, incorrect statistical tests, etc.) and benefits (ease of use) of not correcting this assumption violation. If the purpose in building the model is simply to allow a typical buyer or real estate agent to sit down and estimate the selling price of a house, such transformations may be unnecessary or inappropriate for the task at hand. This issue could also open into a discussion on the contrasts and comparisons between data mining, predictive models, and formal statistical inference.

A second issue closely related to the intended use of the model, is the handling of outliers and unusual observations. In general, I instruct my students to never throw away data points simply because they do not match a priori expectations (or other data points). I strongly make this point in the situation where data are being analyzed for research purposes that will be shared with a larger audience. Alternatively, if the purpose is to once again create a common use model to estimate a “typical” sale, it is in the modeler’s best interest to remove any observations that do not seem typical (such as foreclosures or family sales).

REFERENCES: Individual homes within the data set can be referenced directly from the Ames City Assessor webpage via the Parcel ID (PID) found in the data set. Note these are nominal values (non-numeric) so preceding 0’s must be included in the data entry field on the website. Access to the database can be gained from the Ames site (http://www.cityofames.org/assessor/) by clicking on “property search” or by accessing the Beacon (http://beacon.schneidercorp.com/Default.aspx) website and inputting Iowa and Ames in the appropriate fields. A city map showing the location of all the neighborhoods is also available on the Ames site and can be accessed by clicking on “Maps” and then “Residential Assessment Neighborhoods (City of Ames Only)”.

SUBMITTED BY: Dean De Cock Truman State University 100 E. Normal St., Kirksville, MO, 63501 [email protected]