Described is a method of determining the relative risk of an outcome based on an analysis of multiple risk factors. A graphical method is used to take values corresponding to risk parameters and an event outcome to produce a smoothed surface map representing relative risk over an entire space defined by n risk factors. Applying a query data point to the surface map permits the determination of the estimated outcome probability for the query data point, based on its location on the surface map. The method then reports a relative risk or other probability measure associated with the query data point. Also described is a method of analysis in which subpopulations previously identified as high-risk can be further analyzed with respect to risk posed by additional factors.