Classifier Pooling for Modern Ordinal Classification

TL;DR

This paper introduces a flexible, model-agnostic approach to ordinal classification that leverages existing non-ordinal classifiers, supported by an open-source Python package and validated on real-world datasets, often outperforming traditional methods.

Contribution

It presents a novel, model-agnostic ordinal classification method and provides an open-source Python package for practical application.

Findings

Models often outperform non-ordinal methods on small datasets.

Performance improves with more classes of outcomes.

Software facilitates modern machine learning for ordinal data.

Abstract

Ordinal data is widely prevalent in clinical and other domains, yet there is a lack of both modern, machine-learning based methods and publicly available software to address it. In this paper, we present a model-agnostic method of ordinal classification, which can apply any non-ordinal classification method in an ordinal fashion. We also provide an open-source implementation of these algorithms, in the form of a Python package. We apply these models on multiple real-world datasets to show their performance across domains. We show that they often outperform non-ordinal classification methods, especially when the number of datapoints is relatively small or when there are many classes of outcomes. This work, including the developed software, facilitates the use of modern, more powerful machine learning algorithms to handle ordinal data.