“…Ordinal regression is a machine learning task which aims to predict variables that take values in an ordered and non-numerical set. It is an interesting research topic with applications in many areas, such as weather forecasting (Guijo-Rubio et al, 2020), medicine (Kuráňová, 2016;Sánchez-Monedero et al, 2018;Beckham & Pal, 2017), psychology (Bürkner & Vuorre, 2019), social media mining (Chakraborty & Church, 2020) or computer vision (Antoniuk et al, 2016;Fu et al, 2018;Liu et al, 2017). This type of problem arises in many situations with human labelers, since they usually prefer to quantify data using categorical values rather than continuous values.…”