Methods, systems, and apparatus, including computer programs encoded on a computer storage medium, for training a plurality of different types of predictive models using training data, wherein each of the predictive models implements a different machine learning technique. One or more weights are obtained wherein each weight is associated with an answer category in the plurality of examples. A weighted accuracy is calculated for each of the predictive models using the one or more weights.
Please help me write a proper abstract based on the patent claims. CLAIM: 1. A computer-implemented method, the method comprising: obtaining training data comprising a plurality of examples wherein each example comprises one or more features and an answer; training a plurality of different types of predictive models using the training data, wherein each of the predictive models implements a different machine learning technique; obtaining one or more weights wherein each weight is associated with an answer category in the plurality of examples; calculating a weighted accuracy for each of the predictive models using the one or more weights; and selecting one of the predictive models as a most accurate model based at least partly on the calculated weighted accuracies. 2-30. (canceled)