For the subject test or the general GRE?
For the Subject GRE, since you have to identify the four free schools prior to taking the test, and it takes several weeks to get your scores, you will not be able to see the scores before you select your free schools. More info/source:
https://www.ets.org/gre/subject/about/scoreselect/
For the General GRE, if you take the exam on the computer then you will be able to see your Verbal and Quantitative scores prior to selecting which schools to send your scores to. But if you take the exam on paper then it is like the subject test---you can't see the scores before you choose who gets them. More info/source:
https://www.ets.org/gre/revised_general/scores/send/
There are many different strategies/advice you could employ for selecting the four free schools in the cases where you cannot see your score ahead of time. For example,
1. Don't worry about it and send to the four schools you are the most interested in. If you are not planning on retaking the test, then you'll have to send this score anyways, no matter what it is. So, just send them to the schools you will apply to for sure and take advantage of the free score reports.
2. If you're applying to a large number of schools, then you can probably rank how interested you are in each school and then send them to the bottom 4 of your list of schools that you are certain to apply to. This lets you ensure you use all your free reports but also lets you retake the exam for your top choice schools, if necessary.
3. A variation on the above is to research the schools you're applying to more closely and send the free score reports depending on how much each schools cares about the Subject GRE score. Then you could either send the score reports to the schools that care about them the most or the least, depending on whether you want to maximize your chances at retaking and getting a better score (send free reports to the schools that care about it the least), or if you want to ensure you send as few reports as possible (send free reports to the schools that care about it more).
4. If money isn't an issue for you and if you plan on retaking the test for the ideal score, then don't send any free score reports.
A few additional notes/thoughts:
- Years ago, before ScoreSelect, people basically just did Option 1. Back then, sending a score report meant they saw all of our test scores, so there was no need to fret too much about which schools gets the free reports since even if you retook the test, the school would see both scores. Since most people do not plan on taking the test more than once, with ScoreSelect, I think Options 1 or 2 make the most sense.
- Note that many programs, especially those in astronomy, are now either not requiring or even not accepting Physics GRE scores, so don't waste your free reports on those schools.
- In addition, a bunch of programs are also happy to just receive an unofficial score report or accept self-reported scores and will only want an official report once you are accepted. If you can identify these programs, you might want to not send the free report to them and instead just pay the 27 USD only after you are accepted and decide that you want to go there.