Gene Spafford- American professor of computer science at Purdue University

We need a method of sifting through hundreds, if not thousands, of applications for our program alone. The university has multiple programs, and there are thousands of universities. That presents a lot of decisions to be made, and huge investment in time and energy. It is not surprising that we want some tools to make that simpler and yet still accurate.

Yes, we can look at transcripts, but if they are from institutions we don't know anything about, then how do we rank them? A 4.0 GPA at one institution might be the result of the student doing minimal work, cheating on exams, or even bribing the instructors! However, it could also be that it is a small school with rigorous instruction and a 3.5 GPA from there is outstanding.

We could look at letters of recommendation, but if they come from people we have never heard of before, how do we compare them? They could be letters from very savvy individuals who really know the strengths and weaknesses of the candidate. Then again, the letters could be from cousins of the candidate, and some might be forged.

We can gain some insight from the application essay of a candidate that show thoughtful and careful analysis, but we have also seen cases where the applicants paid someone else to write the essay.

In short, we need some other discriminator to help us understand the quality of candidates — the above measures might work, but they only work in the cases where we know well all the institutions and recommenders.

The GRE is imperfect, but it provides a reasonably independent ranking of basic competency that we can use in addition to all those other items. A student with a 3.5 GPA from a school we never heard of with strong GRE scores is most probably a good candidate, while a students with a GPA of 4.0 from some other unknown school and terrible GRE scores is probably as good a prospect.

In our interdisciplinary grad program, we don't require a GRE score if the student has an undergrad degree from an accredited US college because we can figure out the norm based on what we already know. We can usually do that for well-known colleges in other places — Canada, the UK, Australia — and for a few places in India, China, and elsewhere. However, there are a lot of schools we don't know anything about. Plus, sadly, several countries have a culture of cheating on exams and in class that result in inflated scores that do not accurately reflect the capability of students to succeed in our program.

The GRE can also provide a check on the TOEFL scores, too. Someone with a high TOEFL score who does poorly on the GRE is a indication something isn't quite right.

Ultimately, we have limited space available in the program. We want to ensure that as many students with an excellent chance of success are admitted as possible.

As for the material on the GRE, yes, it is possible to look a word up in a dictionary, or look up an equation online. However, it is important to learn when to look something up, and where and how to use it. Being familiar with those items and knowing how to use them is an important measure of basic preparation and competence. Furthermore, having worked with some of those things enough to have memorized them also results in a certain level of rigor of thought and problem-solving, and an ability to act correctly quickly.

Consider if you went to your doctor because you felt ill. If the doctor had to look up every symptom to get a clue what was wrong, would that be the same as being able to diagnose you without that? If your doctor didn't happen to realize you needed to be checked for high blood pressure, and thus never bothered to look that up, what would be missed? And if you showed up with blood spurting out of a finger, would you want the doctor to then spend time looking up how to stop bleeding and suture a wound?

Experience and knowledge are important.

The GRE doesn't have very advanced concepts on it, because we don't expect every applicant to have had exposure to advanced concepts. Yet. That is why they are applying for admission here! The GRE is intended to test on common, basic concepts that anyone with reasonable preparation should have. If we want proof of greater exposure, we would seek out something such as a GRE subject matter test score (for example).

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