Abstract: A testing method enables the selection, prediction, and validation of any skill using physiological assessments, performance, and subjective responses, using a model. Determining aptitude for a task includes identifying core components of a skill related to the task, testing a first group of individuals known to possess expert skills for the task, including testing physiological response, task performance, and subjective values. Next, using statistical analyses, one or more skill indices are calculated using Bayesian classifiers, support vector machine logic, neural network logic, or regression, to produce skill indices. Next, a second group of individuals not known to possess expert skills are given the same testing, and the statistical model is used in a comparison of the second group with the first group, to predict aptitude for the task.