I used to be one of those believers of quality over quantity, particularly when we're talking about education. "Used to" because now I've become more skeptical after reading Victor Lavy's latest NBER entitled, "Do Differences in School's Instruction Time Explain International Achievement Gaps in Math, Science, and Reading? Evidence from Developed and Developing Countries." In a nutshell, Lavy finds that for education, quantity actually matters. In estimating the effects of instructional time on students' academic achievement in math, science, and reading:
"[t]he evidence from a sample of 15 year olds from over fifty countries that participated in PISA 2006 consistently shows that instructional time has a positive and significant effect on test scores."
Of course, like all things increasing, such increases in intructional time should have a marginal effect. That means there is an optimal level of instructional time where the benefits are maximized--anything more would be economic waste. This is somewhat evident in one of Lavy's other findings:
"However, the estimated effect of instructional time in the sample of developing countries is much lower than the effect size in the developed countries."
Now, I'm saying that this is evidence of the law of diminishing returns because, being a product of an educational system of a developing country, I have observed first hand one of the differences, in terms of instructional time, between the U.S. and a developing country.
In the Philippines, education starts at age 4 with Pre-school, 5 with Nursery, 6 with Kindergarten, and then Elementary Grades 1 to 6 starting at age 7. Then we have four years of high school. That means 9 years of pre-high school education (13 years pre-college). By most standards, that's high in terms of instructional time. Furthermore, we already start learning Mathematics and Science at first grade (age 7). So, it may not be a surprise that Lavy's finds that the estimated effect of instructional time in developing countries is much lower than that of developed countries--the level of instructional time may be high enough already that any additional time would definitely lead to lower effects.
Well, granted that Philippines is not one of the developing country samples in Lavy's study, but chances are we can see similar education systems among developing countries as that of the Philippines.
Just one caveat. Okay, I give in--quantity matters. But still, let's not forget about quality. If the quality of those extra quantity is of low value, then such increase in quantity may not matter at all.
Haha. One more point for the "quality" team.