BigML has been always using confidences (a pessimistic approach) to measure the certainty of a given prediction. Now you can decide to also see probabilities for model predictions. The fundamental difference between both measures is that probabilities don't penalize a lower number of instances in a given node so heavily.

You can see how the three different model visualizations change by playing with the buttons to show confidences or probabilities at the top of the model view.

As we know that cleaning up data might be hard and having all the input data handy at prediction time is important, we have built a new option to create models that will generate predicates that explicitly deal with missing values.