“…Usually, there is a trade-off among the different objectives: for instance, between the performance of a model and training time (increasing the accuracy of a model often requires larger amounts of data and, hence, a higher training time; see e.g., Rajagopal et al (2020)), or between different error-based measures (e.g., between confusion matrix-based measures (Tharwat, 2020) of a binary classification problem; see Horn and Bischl (2016)). Considering these trade-offs is often crucial: e.g., in medical diagnostics (de Toro, Ros, Mota, & Ortega, 2002), the simultaneous consideration of objectives such as sensitivity and specificity is essential to determine if the machine learning model can be used in practice. The goal in multi-objective HPO is to obtain the Paretooptimal solutions, i.e., those solutions for which none of the objectives can be improved without negatively affecting any other objective.…”