1. A computer-executable method for using machine learning to predict an outcome associated with a medical condition, the method comprising: receiving training data including a plurality of records associating feature variables with outcome variables corresponding to at least one medical condition, wherein the training data comprises a first data set associated with a first outcome and comprises a second data set associated with a second outcome substantially less likely than the first outcome; identifying within the first data set a third data set that consists essentially of nearby neighbors to the second data set; and using a plurality of software-based, computer-executable machine learners to develop from the first, second and third data sets at least one set of computer-executable rules usable to predict the first outcome or the second outcome.