Property Valuation by Machine Learning and Hedonic Pricing Models : A Case study on Swedish Residential Property

Sammanfattning: Property valuation is a critical concept for a variety of applications in the real estate market such as transactions, taxes, investments, and mortgages. However, there is little consistency in which method is the best for estimating the property value. This paper aims at investigating and comparing the differences in the Stockholm residential property valuation results among parametric hedonic pricing models (HPM) including linear and log-linear regression models, and Random Forest (RF) as the machine learning algorithm. The data consists of 114,293 arm-length transactions of the tenant-owned apartment between January 2005 to December 2014. The same variables are applied on both the HPM regression models and RF. There are two adopted techniques for data splitting into training and testing datasets, randomly splits and splitting based on the transaction years. These datasets will be used to train and test all the models. The performance evaluation and measurement of each model will base on four performance indicators: R-squared, MSE, RMSE, and MAPE.   The results from both data splitting circumstances have shown that the accuracy of random forest is the highest among the regression models. The discussions point out the causes of the models’ performance changes once applied on different datasets obtained from different data splitting techniques. Limitations are also pointed out at the end of the study for future improvements.