Worker Similarity-Based Label Completion for Crowdsourcing

In real-world crowdsourcing scenarios, it is a common phenomenon that each worker only annotates a few instances, resulting in a significantly sparse crowdsourcing label matrix. Consequently, only a small number of workers influence the inferred integrated label of each instance, which may weaken the performance of label integration algorithms. To address this problem, we propose a novel label completion algorithm called Worker Similarity-based Label Completion (WSLC). WSLC is grounded on the assumption that workers with similar cognitive abilities will annotate similar labels on the same instances. Specifically, we first construct a data set for each worker that includes all instances annotated by this worker and learn a feature vector for each worker. Then, we define a metric based on cosine similarity to estimate worker similarity based on the learned feature vectors. Finally, we complete the labels for each worker on unannotated instances based on the worker similarity and the annotations of similar workers. The experimental results on one real-world and 34 simulated crowdsourced data sets consistently show that WSLC effectively addresses the problem of the sparse crowdsourcing label matrix and enhances the integration accuracies of label integration algorithms.