spb/wp5_uqo Public

1% Author: Simon-Pierre Boucher — contact@spboucher.ai2% =============================================================================3% appendix_robustness.tex — Additional robustness tables4% =============================================================================5\section{Additional Robustness Results}\label{app:robustness}67This appendix presents additional robustness checks that supplement the results reported in Section~\ref{sec:robustness}.89\subsection{Full Regression Output --- Baseline Hedonic Model}1011The preferred hedonic rent specification (Model~1c in Table~\ref{tab:hedonic_rent}) includes property controls (bedrooms, bathrooms, building type) and city fixed effects. Full regression output including all control variable coefficients and city fixed effects is available upon request.1213\subsection{Correlation Matrix of Airbnb Exposure Measures}1415The pairwise correlation matrix of the Airbnb exposure variables at the 500\,m buffer radius documents the degree of collinearity among alternative exposure measures. The various exposure measures---count, density, share of entire-home listings, mean price---are positively correlated, reflecting the spatial concentration of Airbnb activity.1617\subsection{Quantile Regression --- Full Coefficient Tables}1819The quantile regression results reported in Table~\ref{tab:quantile} focus on the Airbnb exposure coefficient across the rent distribution. Full coefficient tables including control variables at each quantile are available upon request.2021\subsection{Machine-Learning Cross-Validation Results}2223Table~\ref{tab:ml_performance} in the main text reports hold-out sample performance for all machine-learning models. The gradient boosting and random forest models achieve substantially higher $R^2$ on the test set relative to linear models, suggesting meaningful nonlinearities in the rent--amenity relationship.2425\subsection{Additional Subsample Results}2627The subsample analysis in Section~\ref{sec:robustness} examines Montreal versus non-Montreal and apartment versus house subsamples. Additional subsample results (e.g., by Airbnb exposure quartile or by borough-level regulation status) are available upon request.28