sat and act
Take both.... I believe SAT is letting you choose whether to report it now or not... check it out. If you really bombed it, you could possibly keep it private... but I believe the academies like to see that you keep trying and keep trying to raise the score....ChristCorp is dead on in explanation as usual.
They(academies) do what is called Superscoring.. take the best for each of the different tests.. like his SAT example. Take it 3 times they take the higest of each of the scores and make that the composite..
In addition she was told by USNA admissions counselor that they (Navy) mix the SAT and ACT together.. and convert them to an SAT-like score. Not sure how true that is or if any of the others do it...but my daughter scored pretty high in Math on ACT versus the SAT.. but much better on SAT Verbal than ACT...the writing sections were equivalent. I know when she went to SS the AFA said they would not mix those two tests...(as in superscoring).
Some people do much better on SAT than ACT and vice versa.. for the most part I believe the people I know did better on ACT.. and this seems to be reflected on this thread as well. The key would be to take practice tests.. you can do a lot on the SAT to bring it up.. a lot.
The trick on the ACT science section is to skip the paragraphs of backround information, look at the graphs/charts etc. and then the questions.. there is a lot of extraneous information that wastes your time, but you can usually pick it out pretty quickly to answer the question. The time compression for science was what my daughter had to most difficulty with on the ACT.
Good luck.. and remember all these tests from academic to cfa are like the old joke.. "how do you get to Carneige Hall?" "practice, practice, practice"