Deprez, LaurensAntonio, KatrienArts, JoachimBoute, Robert2023-02-152023-02-1520230167-637710.1016/j.orl.2023.01.006http://hdl.handle.net/20.500.12127/7163We describe a data-driven approach to optimize periodic maintenance policies for a heterogeneous portfolio with different machine profiles. When insufficient data are available per profile to assess failure intensities and costs accurately, we pool the data of all machine profiles and evaluate the effect of (observable) machine characteristics by calibrating appropriate statistical models. This reduces maintenance costs compared to a stratified approach that splits the data into subsets per profile and a uniform approach that treats all profiles the same.enAttribution-NonCommercial-NoDerivatives 4.0 Internationalhttp://creativecommons.org/licenses/by-nc-nd/4.0/Preventive MaintenanceData PoolingProportional HazardsSmall DataOperations Research Letters1872-7468102358