The ISEE is given several times throughout the year, but the majority of the testing dates fall during the fall and early winter. The number of available ISEE test dates will depend on your location, and you can take the ISEE only once in a six month period. Register now. What's the difference between the SSAT® and the ISEE? Both the ISEE and the SSAT are used for admission to private middle and high schools and test Vocabulary, Math and Reading Comprehension. Many schools will accept either test for admission, which gives you the option of choosing the test that better suits you and your abilities. The major difference between the tests is in how they test your abilities in each section of the exam. The ISEE uses synonyms and sentence completion to test vocabulary, while the SSAT uses synonyms and analogies. The reading passages on the ISEE tend to be longer than those on the SSAT, but the SSAT includes a broader range of genres, including poetry. The ISEE also places a heavier emphasis on mathematical reasoning than the SSAT does. If the schools you're applying to will take either test, choose the one that's better suited to your abilities.