<p>some kids do much better in ACT over SAT and some do much better in SAT over ACT. As far as I know, ACT tests what you know and SAT tests your ability to reason. </p>
<p>There are three sections of SAT, if I remember it right, math, critical reading and writing. </p>
<p>Both my kids do well in ACT so I know little about SAT. Since ACT is knowledge based, one would expect that taking it in senior year should get better scores than in junior year.</p>