vaughn writes:

One relevant sim test that I have been proposing for years is to simply do it
the other way around; go from the left seat to the sim! As an initial test of
any sim, simply have a real pilot (but one who does not fly sims) who is fully
qualified and current on the plane being simulated, sit down and attempt a
takeoff, pattern, and landing. If the "real" pilot can't do that simple task on
the first try, (as the pilot surely could in the real airplane) then the sim
fails .

Even a properly configured desktop simulator can often pass this test.