The host of APTOS 2019 Blindness Detection, Aravind Eye Hospital, asked participants to develop a machine learning model to speed up diabetic retinopathy detection. Participants were provided fundus photography and labeled data based on clinician ratings for the severity of diabetic retinopathy. The competition was evaluated using the quadratic weighted kappa.

Quora is a platform that allows users to ask and answer questions. In the Quora Insincere Questions Classification competition, participants were asked to identify insincere questions –defined as false questions that were intended to make a statement or were founded on false premises. The competition was evaluated using the F1 Score, which gives equal importance to precision and recall.

Founded by both Jigsaw and Google, the Conversation AI research initiative asked participants in the Toxic Comment Classification Challenge to develop a model that classifies text as toxic - threat, obscene, insult, and identity hate. The data was sourced from Wikipedia’s talk page edits. The competition was evaluated using the ROC AUC, a scale-invariant metric that measures how well predictions are ranked.