Letter grades evolved out of higher education in the late 1800s and became the ubiquitous method of evaluating and reporting on student performance during the industrial age when we shifted from one-room schoolhouses to mass produced, factory-model education. While the standardization provided system benefits, the primary value of grades and grade-point averages are that they provide an efficient method to rank, sort, and select students. The strong reliance on grade-point averages as one of the key criteria for higher education admission is an example of such utility.
It is also true that letter grades have proven to be an imperfect approach with some serious limitations that should compel us to reconsider whether the efficiencies gained from their usage outweigh the disadvantages. For example, averaging performance on assignments, quizzes, and tests does not accurately reflect what a student actually knows at a given point in time. Even more alarming is the synthesis of research conducted by Lahey that included the following: