DSA is a way to place students in word study. The test is a spelling test with 25 words on it. The teacher makes a guess as to where most kids in the class will be and tests the class. If a student does very bad or very good on the test, they will give another test (a higher or a lower level) to get the correct placement. Your ds spelled 22 of 25 right in September in Letter Name. You can see the improvement in Within Word between September and December. He got 4 right in September and 23 right (all out of 25) in December. So he is making progress.
Letter name is the first stage, and it is about identifying starting sounds, ending sounds, etc. Within word is next and they work on blends and vowel sounds (like long a vs. short a) and the patterns that make those sounds. I can't remember the name of the next stage offhand.
There's a little more to scoring than just how many he got right out of 25. There are 5 levels in each stage, and there are 5 words on the spelling test devoted to each stage. That helps with placement within the stage.
Word study is supposed to help with spelling, but I think it works best when they start it early, like first grade.
