Label Consistency-Based Ground Truth Inference for Crowdsourcing

In crowdsourcing scenarios, we can obtain each instance's multiple noisy labels from different crowd workers and then infer its unknown ground truth via a ground truth inference method. However, to the best of our knowledge, the existing ground truth inference methods always attempt to aggregate multiple noisy labels into a single consensus label as the ground truth. In this article, we aim to explore a new strategy, i.e., label selection, which directly selects the label of the highest quality worker as the ground truth. To this end, we propose a label consistency-based ground truth inference (LCGTI) method. In LCGTI, we argue that high-quality workers should have a low bias with other workers in labeling the same instances and a low variance with themselves in labeling similar instances. To estimate the bias, we calculate the label consistency of different workers on the same instances. To estimate the variance, we calculate the label consistency of the same worker on similar instances. Finally, we combine these two components to calculate the labeling quality of each worker on the inferred instance and perform label selection instead of label aggregation to achieve inference. The experimental results on 34 simulated and two real-world datasets show that LCGTI significantly outperforms all the other state-of-the-art label aggregation-based ground truth inference methods.