Interesting physical questions frequently require the creation of
complex computational models, furthermore really interesting questions
require models of such complexity that sampling their output over the
full phase space of the problem would require semi-infinite amounts of
computer time. A further fundamental problem with computational models
is to ascertain how well the model adequately represents reality?
I will discuss a method to mitigate the former issue by the construction of an emulator, or surrogate for the computational model which provides a probability distribution for the model's output at all locations in the parameter space. I outline a method for using the emulator, along with field data, to validate the model and it's departure from "reality". The emulator may also be used to globally estimate the sensitivity of the underlying model upon it's parameters.