Explain why GPA is not sound by measurement theory.

"For grade points to be averaged, then grade points must be an interval scale. This implies that the difference between values is comparable. That is, the difference between an A and a B is the same as the difference between a D and an F. Normally, this is not even considered when allocating grades."

"Degrees inside realm of schooling are generally consistent sizes regarding varying levels of comprehension with a discipline. Marks may be designated with characters (by way of example, A, M, H, Deb, or even P oker), as a variety (one example is several.0–i.nought), like a amount beyond a possible entire (e.g. beyond something like 20 as well as 100), while descriptors (outstanding, great, acceptable, desires development), inside proportions, or maybe, as is also popular using some write-up-supplementary organizations in most nations around the world, being a Grade Point Average (Grade point average). Grade point average is definitely determined if you take how many degree things students attained within a offered period of time split with the total number involving credit consumed."