Quality and Agreement in Multilabel Emotion Annotation: A Case Study and Evaluation Framework

2026-06-18

AI Summary

This study addresses the common yet often overlooked issue of subjective disagreement in multi-label sentiment annotation, which traditional approaches typically treat as noise and discard along with its underlying structural information. To better capture annotator uncertainty, the work proposes replacing hard majority voting with soft labels derived from vote proportions and intensity-weighted confidence, and introduces Soft Bernoulli Cross-Entropy (SoftBCE) for soft-supervised model training. Additionally, it incorporates a probabilistic alignment metric for evaluation and a data-driven diagnostic framework to analyze annotation discrepancies. Experimental results show that while hard labels yield marginally higher F1 scores, soft labels more faithfully represent the inherent uncertainty among annotators. This research establishes a novel paradigm and offers practical guidance for label aggregation, model training, and evaluation in multi-label sentiment analysis.

Abstract

Emotion annotation is inherently subjective, yet most NLP pipelines still assume "gold" labels, typically produced by majority voting, and treat annotator variation as noise. In this paper, we present a multilabel emotion annotation case study and use it to examine how annotator behavior and aggregation choices affect both agreement estimates and downstream emotion classifiers. Rather than collapsing disagreement into a single label, we represent targets as soft vote-share labels (including an intensity-weighted variant) and evaluate models using both thresholded metrics (macro-/micro-F1) and probabilistic alignment (Bernoulli cross-entropy SoftBCE), alongside data-derived disagreement diagnostics. Across annotation regimes, we show that disagreement is structured and leaves measurable traces in model behavior: hard labels may maximize F1 metrics, while soft supervision yields predictions that better reflect empirical annotator variance and uncertainty. Our results provide practical guidance for designing, aggregating, and evaluating multilabel emotion datasets when multiple interpretations are plausible.

Problem

• emotion annotation
• subjectivity
• annotator disagreement
• multilabel classification
• label aggregation

Innovation

• soft labels
• emotion annotation
• annotator disagreement
• multilabel classification
• SoftBCE