<p>I just looked into The Real ACT Prep Guide, Cracking the ACT, Kaplan ACT Premier, and McGraw Hill books and they all have a different grading scale for their practice tests. Is it safe to say that The Real ACT Prep Guide is the most accurate since it contains real ACT tests?</p>
<p>well yes the red book has the most accurate grading, since they are real tests.
but every test may have different scales</p>