GIA found that their observations matched only 58% of their computer 'metrics' for WLR (brilliance – then brightness) and DCLR fire research. In the Foundation article there is an admission that scintillation and contrast were the reason for the 42% error factor.

In 1998 in the Brilliance article it was stated the study of cut would require metrics for brilliance, fire and scintillation. In the Foundation article GIA states:

"we did not believe that developing a specific "scintillation metric" was the right approach. (Recall that most of the sparkle aspect of scintillation was already being captured in our metrics for brightness and fire;"

This is a circular argument.

Using our Steep Deep stone (C) as an example, by estimation approximations from the charts in the two Brilliance and Fire articles, this diamond receives only 0.277 WLR (low 'typical') and 3.0 DCLR (low 'average') 'brilliance' and 'fire' metrics. Deeper pavilion diamonds (with thinner pavilions) with even lower WLR and DCLR scores are predicted

Therefore it is probably not a coincidence that there are no WLR or DCLR data listed in the Foundation article for the 45 mater stones.