To determine which test to take, students should take a diagnostic of both to see which one fits them best.
Note: Because the ISEE can only be taken once in any given testing season (Fall: August t0 November. Winter: December to March. Spring: April to July), students are likely to only have one try on the ISEE when they are fully prepared for it. There is variability in any test date: Students could have a good or bad day, the content tested on that test date might fit them particularly well or not, etc. Given that variability, there’s higher risk inherent with going with the ISEE. For that reason, if a student scores significantly higher on the ISEE, they should prepare for the ISEE. If they only score slightly higher on the ISEE diagnostic, then it’s still safer for them to prepare for the SSAT, because they can easily take the SSAT multiple times. And, if a student does prepare for the ISEE, they still might want to register for and take an SSAT as a back-up, just in case they get unlucky on the ISEE test day and the test does not go as planned.