The study employs the presale housing market survey data of the Cathay Real Estate Development Company to establish presale housing hedonic models. To observe the effects of outliers, ordinary least squares (OLS) is employed as a benchmark to compare the model performance of two outlier deletion techniques, DFFITS and least trimmed squares (LTS). LTS is aimed at fitting a regression model to most of the data while identifying the outliers as the points with large residuals. By giving a zero weight to the cases with residuals larger than a threshold value, the outliers are disregarded in the following OLS calibration process. The technique is referred to as reweighted least squares (RLS). The results demonstrate that: 1. the RLS regression and DFFITS models outperform the OLS models; 2. most outliers come from a specific area and product positioning from specific districts; and 3. in the long term, these different estimation techniques do not affect housing price indices-however, if we observe the movements season by season, the different estimation techniques yield different price movements, which affect the interpretation of short-term presale housing market data.