Evaluating Equivalent Monte Carlo Calculations

We address several basic issues, primarily whether two sets of MCNP tallies are stochastically equivalent (i.e., that the sets of particle history scores follow the same statistical distribution) and, if different, quantify the significance level of the difference. The underlying topics here are of longstanding interest to the statistical community, and no “new” theoretical work needs to be carried out to address them. Related comparisons are useful to code developers in assessing code modifications and to code users in assessing other simulations and related physical measurements. However, these statistical methods must be applied with care to avoid obtaining misleading results, as we show in several examples. The text is written for MCNP practitioners.