On grade inflation

Has the US been experiencing a grade inflation? It is a fact that the average grade a student receives has been increasing over the past decades. Yet, this does not suffice to claim that there is a grade 'inflation' since to do so we must assume that the student ability has not changed over time.

First, we must agree on whether grade should be measured relatively or absolutely. In many cases, grades are measured relatively; a student grade often reflects how many standard deviations he is away from the median student of the class. In this case, grade inflation translates to a higher GPA number assigned to the median student. Yet, we would at least like to measure grades absolutely. In other words, grade should reflect the degree to which the student has achieved the course objectives. The relative measure is merely one way to overcome the difficulty of objective absolute grading.

If grades are measured absolutely, then the grade inflation must look not only at the time trend of the average grade, but also at the change in average student achievement. If students are on average learning more efficiently and therefore meet the course objectives to greater degree, then the average grade should increase. It is difficult to find empirical data on the degree student achievement since it is most commonly measured by GPA. There are, however, good reasons to believe that students on average learn better than they did before. The argument comes from two sides.

One side is that the college has become increasingly competitive. A fact: the average acceptance rate to universities is decreasing. There would be many reasons for this: increasing population, increasing returns to education, and decreasing transportation cost which increases the candidate pools by bringing international students. No matter what the reason is, it is undeniable that the selection to the university is becoming increasingly competitive, and therefore, if we believe that admission committee does its job and selects more able students from the candidate pool, then we should believe that the average ability of students is increasing.

On the other side, teaching become more efficient over the past decades. Students today have access to better textbooks, greater resources (much thanks to the Internet), and hopefully better teaching methods (due to slow but existing pedagogical progress), compared to students in the past. We would at very least hope that these improvements help students to learn, in which case an average student would achieve more learning objectives now than in the past.

This argument counters a claim that grade inflation causes students to be more lazy. To the contrary, it is an increase in learning efficiency that causes the seeming grade inflation. The only concern with the inflation is then that GPA may lose its signal value, but then again, that might not be a bad thing.