A method for detecting the occurrence of rare events in an executable logic code includes assigning a first probability of a chance of traversal of one or more decision paths, in which each path connects two decision points defined by execution of the logic code. As a result of execution of the logic code, the decision paths traversed are evaluated to determine whether said traversal conforms to a predefined performance function. The performance function defines a goal to be achieved pursuant to the execution of the logic code. A second probability is assigned to the chance of traversal of at least one of said one or more decision paths to increase the likelihood that the one or more decision paths are traversed in a subsequent execution of the logic code in a closer conformity with the predefined performance function.