The computer system applies machine learning techniques to train a computational model using data representing researched items and their known properties. The computer system applies the trained computational model to data representing the potential candidate items to predict whether such items have such properties. The trained computational model outputs one or more predictions about whether the potential candidate items are likely to have a property from among the plurality of types of properties that the computational model is trained to predict. The computer system allows multiple machine learning experiments to be defined, and then allows predictions from those multiple machine learning experiments to be queried, including accessing aggregate statistics for those predictions. In some implementations, a machine learning experiment can specify a computational model that is an ensemble of multiple models.