1. A medical outcome prediction tool encoded with instructions in a tangible computer readable medium for predicting an individual's medical outcomes from at least one computer database storing electronic medical data for a patient population, wherein execution of the instructions by one or more processors causes the one or more processors to perform the steps comprising: a. identifying patients within a patient population having a same disease from electronic health records in at least one computer database; b. selecting a set of characteristics from the electronic health records that is unique to an individual among the identified patients; c. determining the similarities between the individual and other cases among the identified patients by: i. calculating the number of matches between the individual and the cases over the set of characteristics; and ii. using the result of the calculated matches to determine a similarity score; and d. calculating an expected outcome for the individual by: i. generating a result by summing the product between the similarity score and a weighted sum of outcomes; and ii. dividing the result by the sum of the similarity score.