1. A method of using stack data and source code to rank program changes, the method comprising: a computer accessing a stack data of a program; the computer accessing a source code of the program; the computer searching for a first change made to the program, wherein the first change is one of a change to a method of the program, a change to a class of the program, a change to a method that is invoked by the program, or a change to a class containing a method that is invoked by the program; the computer identifying the first change that was made to the program; and the computer determining a probability that the identified first change caused one or both of an error and a regression, wherein the probability based on one or more of a type of the change, a time when the change was made, a number of changes made, and a frequency of the change being identified; the computer generating a ranked list of identified changes based, at least in part, on the probability that the identified first change caused one or both of an error and a regression.