A Taxonomy of Rater Disagreements: Surveying Challenges & Opportunities from the Perspective of Annotating Online Toxicity

Toxicity is an increasingly common and severe issue in online spaces. Consequently, a rich line of machine learning research over the past decade has focused on computationally detecting and mitigating online toxicity. These efforts crucially rely on human-annotated datasets that identify toxic content of various kinds in social media texts. However, such annotations historically yield low inter-rater agreement, which was often dealt with by taking the majority vote or other such approaches to arrive at a single ground truth label. Recent research has pointed out the importance of accounting for the subjective nature of this task when building and utilizing these datasets, and this has triggered work on analyzing and better understanding rater disagreements, and how they could be effectively incorporated into the machine learning developmental pipeline. While these efforts are filling an important gap, there is a lack of a broader framework about the root causes of rater disagreement, and therefore, we situate this work within that broader landscape. In this survey paper, we analyze a broad set of literature on the reasons behind rater disagreements focusing on online toxicity, and propose a detailed taxonomy for the same. Further, we summarize and discuss the potential solutions targeting each reason for disagreement. We also discuss several open issues, which could promote the future development of online toxicity research.

RoCourseNet: Distributionally Robust Training of a Prediction Aware Recourse Model

Counterfactual (CF) explanations for machine learning (ML) models are preferred by end-users, as they explain the predictions of ML models by providing a recourse case to individuals who are adversely impacted by predicted outcomes. Existing CF explanation methods generate recourses under the assumption that the underlying target ML model remains stationary over time. However, due to commonly occurring distributional shifts in training data, ML models constantly get updated in practice, which might render previously generated recourses invalid and diminish end-users trust in our algorithmic framework. To address this problem, we propose RoCourseNet, a training framework that jointly optimizes for predictions and robust recourses to future data shifts. We have three main contributions: (i) We propose a novel virtual data shift (VDS) algorithm to find worst-case shifted ML models by explicitly considering the worst-case data shift in the training dataset. (ii) We leverage adversarial training to solve a novel tri-level optimization problem inside RoCourseNet, which simultaneously generates predictions and corresponding robust recourses. (iii) Finally, we evaluate RoCourseNet's performance on three real-world datasets and show that RoCourseNet outperforms state-of-the-art baselines by 10% in generating robust CF explanations.

CounterNet: End-to-End Training of Counterfactual Aware Predictions

This work presents CounterNet, a novel end-to-end learning framework which integrates the predictive model training and counterfactual (CF) explanation generation into a single end-to-end pipeline. Counterfactual explanations attempt to find the smallest modification to the feature values of an instance that changes the prediction of the ML model to a predefined output. Prior CF explanation techniques rely on solving separate time-intensive optimization problems for every single input instance to find CF examples, and also suffer from the misalignment of objectives between model predictions and explanations, which leads to significant shortcomings in the quality of CF explanations. CounterNet, on the other hand, integrates both prediction and explanation in the same framework, which enables the optimization of the CF example generation only once together with the predictive model. We propose a novel variant of back-propagation which can help in effectively training CounterNet's network. Finally, we conduct extensive experiments on multiple real-world datasets. Our results show that CounterNet generates high-quality predictions, and corresponding CF examples (with high validity) for any new input instance significantly faster than existing state-of-the-art baselines.