The CIE 1912 model of performance cannot be used to predict performance or productivity. We present counter-examples to the link assumed in CIE 19/2 between performance and productivity. Statistical arguments show that the fitting parameters are not physically determined as was thought and that the curve fitting in the CIE 1912 report does not constitute a validation.

Some critics of CIE 1912 have suggested that RQQ #6 be used in its place for lighting calculations. RQQ #6 is simply a consensus of present practice. The more robust visibility trends presented in CIE 19/2 are inconsistent with the recommendations in RQQ #6. Careful use of the material in CIE 19/2 could lead to better recommendations than are exemplified by RQQ #6.