Tejas Kiran Chaudhari supervised by Dr. Naresh Manwani received his  Master of Science –  Dual Degree in Computer Science and Engineering  (CSD). Here’s a summary of his research work on Fairness in Abstain Option Classification:

As machine learning models are increasingly adopted in critical decision-making domains, ensuring their fairness has become a central concern — especially when these systems have the option to abstain from making a prediction. While abstain option classifiers reduce the risk of error by deferring uncertain decisions, they may inadvertently introduce new forms of unfairness, particularly when abstention rates differ across sensitive groups. This thesis investigates the fairness implications of abstain option classification and proposes methods to mitigate associated disparities. We present EQUISCALE, a unified framework for training fair cost-based abstain classifiers under group fairness constraints. Unlike prior work that focuses exclusively on coverage-based models and single fairness criteria, EQUISCALE introduces fairness-aware loss formulations that extend demographic parity (independence) and equalized odds (separation) to the abstention setting. The approach uses Lagrangian dual optimization to enforce fairness constraints during model training. EQUISCALE is the first method to incorporate multiple fairness criteria simultaneously in abstain classification and to apply the separation criterion in this context. We validate our approach through extensive experiments on five benchmark datasets, showing substantial reductions in fairness violations without compromising classification performance. This work advances the understanding of fair abstention and provides practical tools for deploying equitable machine learning systems in high-risk environments.

July 2025