  It is often not possible to construct a probability density function that
describes the data. This can happen if there is no analytic description, and
the number of parameters is too large so that it is impossible to simulate and
tabulate all combinations. In these situations it is still interesting to rank
simulation sets performed with different parameters in how well they compare to
data. We propose a solution that appears to be better suited to this task than
some of the obvious alternatives.
