“…Many solutions exist to resolve the low-quality contributions that come either from deliberate scamming or poor performance (Ipeirotis et al, 2010;Dow et al, 2012;Ipeirotis et al, 2014;Gadiraju et al, 2015). The most commonly adopted technique for quality assurance relies on a set of questions with known correct answers, often referred to as gold standard test questions, which are randomly injected into the workers' sessions in order to measure their performance (Checco et al, 2018;Sun and Dance, 2012;El Maarry et al, 2014). In addition, since the original Dawid-Sekene (Dawid and Skene, 1979) crowdsourcing model based on maximum likelihood estimation, several improvements have been proposed: the Fast Dawid-Skene model for improved speed of convergence (Sinha et al, 2018), the effort to extend to multiclass labeling from binary labeling (Li and Yu, 2014), and the Minmax Entropy method (Zhou et al, 2012) for accuracy improvements.…”