House prices in Ames, Iowa
linear regression
nonparametric regression
Records of homes sold in Ames, Iowa, and their sale prices, including detailed covariates that could be used to predict home prices.
Motivation
Estimating the market value of a house is fairly tricky. It depends on many factors: the size of the house, its age, many features of its construction quality, amenities like swimming pools and garages, proximity to parks and good roads, and many other hard-to-quantify features. But many people depend on estimating accurate market values. Realtors estimate values to determine how much to ask for a property, or how much to offer to buy a property; banks estimate values when issuing a mortgage, to know how much they could sell the house for in case the mortgage is foreclosed on; local governments assess values to determine property tax bills; and even casual browsers like to know how much the house down the street would cost.
But the market price of a house is, by definition, how much someone is willing to buy it for. It is not determined by formula but by waiting for someone to buy the house. If nobody has bought the house, can we build a prediction system that predicts its market value, using features of the house?
Data
This dataset was produced by the Ames, Iowa Assessor’s Office to assess the values of houses sold in Ames from 2006 to 2010, and made available by Dean De Cock, Truman State University. It covers 2,930 individual sales, recording features of the house and its actual sale price.
Data preview
ames-housing.csv
Variable descriptions
Most covariates are described below. Additional detail is found in the data documentation file.
| Variable | Description |
|---|---|
| Order | Observation number |
| PID | City parcel identification number |
| MS.SubClass | Dwelling type. See documentation file for categories |
| MS.Zoning | Zoning of the lot. 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 | Linear feet of street connected to the property (such as the street in front of a house) |
| Lot.Area | Lot size (square feet) |
| Street | Type of road connected to the property. Grvl = Gravel, Pave = Paved. |
| Alley | Type of alley connected to the property. (Alleys generally run behind houses and provide garage access.) Grvl = Gravel, Pave = Paved, NA = no alley. |
| Lot.Shape | Shape of the property. Reg = Regular, IR1 = Slightly irregular, IR2 = moderately irregular, IR3 = Irregular. |
| Land.Contour | Flatness of the property. Lvl = near flat/level, Bnk = banked from street to building, HLS = hillside slope from side to side, Low = in a depression. |
| Utilities | Types of utilities available, such as electricity, gas, water, and sewer. AllPub = all public utilities, NoSewr = no sewer (only a septic tank), NoSeWa = no sewer or water, ELO = electricity only. |
| Lot.Config | Lot configuration. Inside = inside lot, Corner = corner lot, CulDSac = cul-de-sac, FR2 = street frontage on 2 sides of property, FR3 = street frontage on 3 sides of property. |
| Land.Slope | Slope of the property. Gtl = gentle slope, Mod = moderate slope, Sev = severe slope. |
| Neighborhood | Location within Ames neighborhoods. Consult documentation file for full names. |
| Condition.1 | Proximity to major roads, railroads, or parks (see documentation for details). |
| Condition.2 | Same as Condition.1, used only if there is more than one feature for this lot. |
| Bldg.Type | Type of house. 1Fam = one family detached, 2FmCon = one-family house converted to a duplex, Duplx = Duplex, TwnhsE = townhouse end unit, TwnhsI = townhouse inside unit. |
| House.Style | Style of the house. See documentation file. |
| Overall.Qual | Overall material and finish of the house. 1 to 10 scale, where 1 = very poor and 10 = very excellent. |
| Overall.Cond | Overall condition of the house, on same 1 to 10 scale. |
| Year.Built | Year the home was originally built. |
| Year.Remod.Add | Year the home was remodeled or added to. Same as the year built if no major remodeling or additions have been done. |
| Roof.Style | Type of roof. Flat = flat, Gable = Gable, Gambrel = Gambrel roof, Hip = Hip roof, Mansard = Mansard roof, Shed = shed. |
| Roof.Matl | Material used for the roof. ClyTile = clay or tile, CompShg = composite shingles, Membran = membrane, Metal = metal, Roll = roll, Tar&Grv = gravel and tar, WdShake = wood shakes, WdShngl = wood shingles. |
| Exterior.1st | Exterior covering on house. See documentation file. |
| Exterior.2nd | Second exterior covering, if the house is covered in more than one material. |
| Mas.Vnr.Type | If the house is faced with masonry, the type of veneer. BrkCmn = common brick, BrkFace = brick face, CBlock = cinder block, None = none, Stone = stone. |
| Mas.Vnr.Area | Area of masonry veneer (square feet) |
| Exter.Qual | Quality of material on the exterior. Ex = excellent, Gd = good, TA = typical/average, Fa = fair, Po = poor. |
| Exter.Cond | Current condition of material on the exterior. Same scale. |
| Foundation | Type of foundation. BrkTil = brick and tile, CBlock = cinder block, PConc = poured concrete, Slab = concrete slab, Stone = stone, Wood = wood. |
| Bsmt.Qual | Height of the basement or crawl space. 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 | General condition of the basement. Ex = excellent, Gd = good, TA = typical (possibly damp), Fa = fair (dampness, cracking, or settling), Po = poor (severe cracking, settling, or wetness), NA = no basement. |
| Bsmt.Exposure | Exposure of the basement to the outdoors, such as through walkout doors. Gd = good exposure, Av = average, Mn = minimum, No = no exposure, NA = no basement. |
| BsmtFin.Type.1 | Rating of the finished part of the basement. GLQ = good living quarters, ALQ = average living quarters, BLQ = below average living quarters, Rec = average rec room, LwQ = low quality, Unf = unfinished, NA = no basement. |
| BsmtFin.SF.1 | Finished square feet in the basement. |
| BsmtFin.Type.2 | If there are multiple types of basement finished area, this is the same as BsmtFin.Type.1 but for the next area. |
| BsmtFin.SF.2 | |
| Bsmt.Unf.SF | Area of the basement that is unfinished (square feet) |
| Total.Bsmt.SF | Total area of basement (square feet) |
| Heating | 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. |
| Heating.QC | Heating quality and condition. Ex = excellent, Gd = good, TA = typical/average, Fa = fair, Po = poor. |
| Central.Air | Does the house have central air conditioning? N = no, Y = yes. |
| Electrical | Electrical system in the house. SBrkr = standard circuit breakers and sheathed wiring, FuseA = fuse box over 60 amps and sheathed wiring, FuseF = 60 amp fuse box and mostly sheathed wiring, FuseP = 60 amp fuse box and mostly knob & tube wiring, Mix = mixed |
| X1st.Flr.SF | First floor area (square feet) |
| X2nd.Flr.SF | Second floor area (square feet) |
| Low.Qual.Fin.SF | Low quality finished area, all floors (square feet) |
| Gr.Liv.Area | Above ground living area (square feet) |
| Bsmt.Full.Bath | Number of full bathrooms in the basement |
| Bsmt.Half.Bath | Number of half bathrooms in the basement |
| Full.Bath | Number of full bathrooms above ground |
| Half.Bath | Number of half bathrooms above ground |
| Bedroom.AbvGr | Number of bedrooms above ground |
| Kitchen.AbvGr | Number of kitchens above ground |
| Kitchen.Qual | Kitchen quality. Ex = Excellent, Gd = good, TA = typical/average, Fa = fair, Po = poor. |
| TotRms.AbvGrd | Total rooms above ground, not including bathrooms |
| Functional | Home functionality. Usually typical. Typ = typical, then deductions in order: Min1, Min2, Mod, Maj1, Maj2, Sev (severely damaged), and Sal (salvage only). |
| Fireplaces | Number of fireplaces |
| Fireplace.Qu | Fireplace quality. Ex = exceptional masonry fireplace, Good = masonry fireplace on main level, TA = prefabricated fireplace in main living area or masonry fireplace in basement, Fa = prefabricated fireplace in basement, Po = Ben Franklin stove, NA = no fireplace. |
| Garage.Type | Type of garage. 2Types = more than one garage type, Attchd = attached to home, Basment = basement garage, BuiltIn = built in to house with room above garage, CarPort = car port, Detchd = detached from home, NA = none. |
| Garage.Yr.Blt | Year the garage was built |
| Garage.Finish | Interior finish of the garage. Fin = finished, RFn = rough finished, Unf = unfinished, NA = no garage. |
| Garage.Cars | Number of cars that fit in the garage |
| Garage.Area | Size of the garage (square feet) |
| Garage.Qual | Garage quality. Ex = excellent, Gd = good, TA = typical/average, Fa = fair, Po = poor, NA = no garage. |
| Garage.Cond | Garage condition (same scale). |
| Paved.Drive | Driveway type. Y = paved, P = partially paved, N = dirt or gravel. |
| Wood.Deck.SF | Wood deck area (square feet) |
| Open.Porch.SF | Open porch area (square feet) |
| Enclosed.Porch | Enclosed porch area (square feet) |
| X3Ssn.Porch | Three-season porch area (square feet) |
| Screen.Porch | Screened-in porch area (square feet) |
| Pool.Area | Pool area (square feet) |
| Pool.QC | Pool quality. Ex = excellent, Gd = good, TA = typical/average, Fa = fair, NA = no pool. |
| Fence | Fence quality. GdPrv = good privacy, MnPrv = minimum privacy, GdWo = good wood, MnWw = minimum wood/wire, NA = no fence. |
| Misc.Feature | Miscellaneous feature not covered in other categories. Elev = elevator, Gar2 = second garage, Othr = other, Shed = shed over 100 square feet, TenC = tennis court, NA = none. |
| Misc.Val | Value of the miscellaneous feature (dollars) |
| Mo.Sold | Month sold |
| Yr.Sold | Year sold |
| Sale.Type | Type of sale. Wd = Conventional warranty deed, CWD = cash warranty deed, VWD = VA loan warranty deed, New = house just built and sold, COD = court officer deed or estate, Con = contract with 15% down payment and regular terms, ConLW = contract with low down payment and low interest, ConLI = contract with low interest, ConLD = contract with low down payment, Oth = other. |
| Sale.Condition | Condition of sale. Normal = normal; Abnorml = trade, foreclosure, or short sale; AdjLand = adjoining land purchase; Alloca = allocation of two linked properties with separate deeds, such as condos; Family = sale between family members; Partial = home was not completed when last assessed (e.g. it was under construction) |
| SalePrice | Price house sold for (dollars) |
Questions
- Use the sale price data and the features of the houses to build a regression or prediction model to predict sale price from house features. Be sure to set aside a test set to test the accuracy of your predictions.
References
D De Cock (2011). Ames, Iowa: Alternative to the Boston Housing Data as an End of Semester Regression Project. Journal of Statistics Education 19 (3). https://doi.org/10.1080/10691898.2011.11889627