1. A computer-implemented method of calibrating a scoring model for scoring examinee responses, comprising: accessing a plurality of training responses with a processing system for training a scoring model for scoring examinee responses, the training responses and examinee responses being constructed responses; analyzing the plurality of training responses with the processing system to derive values of multiple features of the training responses, the multiple features corresponding to variables of the scoring model; training the scoring model with the processing system based on the values of the multiple features of the training responses and one or more external measures of proficiency for each individual associated with a training response utilized in the training, the one or more external measures not being derived from the training responses; determining, based on said training, a weight for each of the multiple features; and calibrating the scoring model to include the weights for at least some of the features such that the scoring model is configured to generate scores for examinee responses.