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.

On school grades

Surely any teacher would be offended by the signaling theory of education. If people who go to school don’t come out any better, what does that imply about teachers? The theory seems to suggest that their only function is to make it costly for low ability students to go to school. I believe that most teachers strive quite the opposite. They would want to see improvements especially among the low ability students.

So why do schools assign grades to students? Grading serves as a mechanism to distinguish high ability students from low ability ones, so that the school can reward the high grade students and/or punish the low grade students psychologically, financially, or even physically.

If a school’s interest is to improve students’ abilities rather than to make itself a signaling mechanism, then it should abandon the grading system altogether. One could argue that grades can be used as incentives for students to work harder, but if this were to be true, then grades need to be based on marginal improvement. In reality, grades are based on comparison with others’ performances rather than with one’s own past performance. There is reasons to think that this form of grading can provide disincentives to put effort for low ability students.

By signaling mechanisms, schools that are harsher to low ability students are more popular, since attending such schools signal that students have high ability. If a grade-free school was introduced, such school would be less costly for low ability students, attendance to such schools will give bad signals, and thus the school will be driven out of the market.

What should we do, then? Make a collective effort to make schools grade-free. Schools, with the aim of improving students' abilities, can function without giving grades. On the other hand, grading system leads to early sorting processes potentially resulting in discrimination against low-income students (holding abilities constant, students from high-income families can more easily earn higher grade, earning potentially life-long advantage through signaling). Further, valuable resources are being wasted on grading in the sense that those resources can be put into better improving students’ abilities. Students want teachers, not graders.

On Freakonomics

It is slightly embarrassing to confess that I have not read Freakonomics until recently, but on the other hand I am somewhat glad that I delayed reading until I had at least some exposure to economics. I believe having some knowledge in economics allowed me to appreciate the book more than I would have otherwise. Many thoughts came to my mind while reading the book, and I’ve been intending to scribble those thoughts down for quite a few days now (Why did I not do immediately after finishing the book, when my thoughts were more vivid? Ask a behavioral economist).

The Q&A section of the book suggests that the chapter on abortion and crime rate was the most controversial one, so I’ll start with that. The gist of the argument in that chapter is that legalizing abortion causes crime rate to go down. The argument does not imply that abortion should be legalized (abortion might be categorically impermissible and even if you believe in consequentialism, you could argue that human life is worth more than reduced crime rate), but one can see why this argument faces unfriendly reaction.

Nevertheless, I think there is more than just the sensitivity of the subject matter that makes the argument controversial. Even if you think abortion should be legalized and are comfortable with the idea of quantifying the value of human life (the authors provide 100 fetuses to 1 new born ratio as an example of relative value of human lives to measure the efficiency of trade-off between abortion and crime rate), the argument is disturbing. Consider the secondary causes of crime rate reduction that the authors suggest, namely the increased number of prisons and police (essentially greater incentive to not commit crime). As authors themselves write, these factors do not “address the root causes of crime.” It almost seems that the only way to get rid of crime is to get rid of criminals before they are literally born. Of course this is not necessarily true since there can be other plausible solutions, but the authors at least suggest that the end we achieved (reduced crime rate) is not the result of the means we wanted. I think this has a significant implication on politics and more specifically liberal ideology, but I will not venture to discuss those here. Economics alone is sufficiently dismal.

What I personally find little more troublesome is the chapter on parenting. The main argument of the chapter is that “it isn’t so much a matter of what you do as a parent; it’s who you are.” This claim, however, comes with a lot of ‘but’s. To start off, it does matter what you do if you are doing bad: “Clearly, bad parenting matters a great deal” (Otherwise it would be difficult to explain why legalizing abortion reduces crime rate). So if you are beating up your children, your children will be affected, but if you are intending to do good, then those actions have no influence.

But there is another catch. The ELCS data show that what you do as a parent doesn’t affect your child’s school performance, not necessarily your child’s whole life. Authors write: “since most parents would agree that education lies at the core of a child’s formation, it would make sense to begin by examining a telling set of school data.” Fair enough, but the story not only begins at the school performance, but it also ends there. So I am convinced that having lots of books in the house or having Mozart music playing all the time won’t improve the child’s school performance, but I am not fully convinced that they don’t matter. The smartness of a child, measured by IQ, probably is the main determining factor of a child’s school performance especially in the early years, and I am willing admit that better neighborhood or museum trips won’t improve the child’s IQ. But as the authors state, school performance is “a useful but fairly narrow measurement… poor testing in early childhood isn’t necessarily a great harbinger of future earnings, creativity, or happiness.” And then the chapter ends with a brief mention of Sacerdote’s research that shows “the influence of the adoptive parents … made the difference [on children’s higher education and career].”

As I believe I exaggerated a little here, the whole chapter on the parenting doesn’t seem to have a strong message. What you do as a parent doesn’t affect your children’s IQs, but it could affect their future careers. I can agree that reading to your children won’t affect their school performances, but I am not convinced it doesn’t matter.

This was all in all a fun and interesting book to read, and I am excited to read Superfreakonomics, but coming up next is Nudge.