Det anerkendes dog, at beregningerne er baseret på en række antagelser, og at der kan forekomme en vis skævhed i oplysningerne, men den unormale statistiske forekomst af SUD synes stadig at forekomme, efter at indvirkningen af nye og forskellige andre antagelser er blevet afprøvet.
However, it is acknowledged that the calculations are based on a number of assumptions and may be affected by bias in the data, but the finding of an excess statistical occurrence of SUD seems to remain after testing for the influence of new and different assumptions.