Many factors that attribute to economic productivity are useful to improving a student's GPA.
First of all, there is the quality of labor. The quality of labor is an immensely important factor contributing to economic success and also success in schools as well. Imagine sitting in front of a desk for ten straight hours trying to study and at the same time also trying to watch a TV show and listen to the newest release of Maroon 5. Those things are bound to distract you from your main goal some how, and you end up studying only three pages. The quality of your intensive ten hour " labor", is therefore, very little.
Second of all, there is the technological innovation. The most prominent example of this in today's schools are computers. Computers and the internet brought more available information to the table. Now a student can enhance him or herself not only from the books they have, but also from the internet. This improves productivity because the student will have more readily available information at their disposal.
Third of all, financial markets. This does not have as big an effect on GDP as do other factors. The financial market CAN impact a student's home life and that can in terms affect their studying environment and therefore their GPAs.
Lastly, energy costs. Energy costs, sadly don't contribute much to the GPA.