Half the score is finished before the test exists
CPS decides Selective Enrollment admission on 640 points. Up to 320 come from the admissions test taken in October of 8th grade — the PreACT 9 Secure, which CPS still calls the HSAT. The other 320 come from one number: the student's final 7th-grade GPA, multiplied by 80.
Read that again with the calendar in mind. The test half happens in the fall of 8th grade, after months of practice, with a countdown and a study plan and a family paying attention. The grade half was decided the year before, quarter by quarter, mostly by a 12-year-old who had never heard the word composite.
By the time a family starts preparing for the test, the grade half is finished. It cannot be practiced, retaken or improved. That is not a warning — it is the reason this page exists. If you are reading this in 7th grade, you are holding the half that is still open, and almost nobody tells you that while it still matters.
What one B costs, in points
The GPA that CPS multiplies by 80 comes from the four core subjects: English, Math, Science and Social Studies. Four subjects means each one is a quarter of the GPA, so one letter step in a single class moves the GPA by 0.25 — and the admissions score by 20 points.
A 4.0 earns the full 320 grade points. Three A's and one B is a 3.75, which earns 300. Two A's and two B's is a 3.5, which earns 280. Straight B's is a 3.0, which earns 240 — eighty points behind a straight-A classmate before either of them has answered a single question on the test.
Twenty points per letter grade is the whole mechanic, and it is worth saying plainly because it is unusually cheap to protect. A B that was a B because of three missing homework assignments costs exactly as much as a B earned on genuinely hard material.
What it would take on the test to make back 20 points
The test half is the composite of English, Reading and Math — Science is on the test and in the score report, but CPS does not count it in the admissions composite — multiplied by 10. So 20 grade points is exactly 2 composite points.
Two composite points, in the middle of ACT's conversion table, means roughly two or three more correct answers in each of English, Reading and Math. In the same sitting. On a timed test. In one morning in October, with no retake.
It is doable — students move more than that with real practice. But it is worth weighing honestly against the alternative: turning in the assignment that was due on a Tuesday in 7th grade.
Which grades count, and when they stop being changeable
CPS uses final 7th-grade grades in the four core subjects. Final means the year's grade, not a single quarter, which is the part worth acting on: a rough first quarter is still recoverable in the second and third. A rough final quarter is not.
Confirm with your school how it reports final grades — schools differ in whether pluses and minuses appear on the transcript and how quarters average into a year grade. The point formula (GPA × 80) is published by CPS; the arithmetic that produces the GPA happens at the school.
Eighth-grade grades do not replace 7th-grade grades in the formula. The application goes in during the fall of 8th grade, before 8th-grade finals exist. That is exactly why 7th grade carries the weight it does.
A 7th-grade year, quarter by quarter
First quarter: find out which four classes count, and check the online gradebook every two weeks instead of at report-card time. Almost every recoverable grade problem is visible six weeks before it becomes permanent.
Second quarter: hunt zeros, not points. A missing assignment scored as a zero drags an average further than a bad test does, and it is the one thing a teacher can usually still accept. Ask what the late-work policy actually is before assuming there isn't one.
Third quarter: if a core subject is sitting on the line between two letters, ask the teacher directly what would move it. A single retake, project revision or set of late assignments is frequently worth the same 20 admissions points that two or three extra right answers on the October test would buy.
Fourth quarter: final grades land and the grade half closes. That is when the test half starts — the summer before 8th grade is the right time for a first diagnostic, with no pressure attached to it.
If the grades already slipped
Nobody re-does 7th grade. What is left is worth saying clearly: the test half is worth exactly as many points as the grade half, and it is entirely ahead of you. A student who lands 300 test points with 260 grade points is at 560, which beats a straight-A student who walks in cold.
Two structural facts also matter. First, 70% of Selective Enrollment seats are distributed within the four tiers, so a composite is compared against students from similar census block groups, not against the whole city. Second, Selective Enrollment is not the only competitive path in CPS: of the 21 program types on this site, ten fill their seats mainly by lottery, without the admissions test, and IB programs add a 35-point geographic bonus for applicants inside the school's area, raising their ceiling to 675.
And one honest caveat that applies to every number a family will see this year: no cutoffs exist on the 640-point scale yet. CPS publishes the first ones after February 2027 results. Any target score quoted today is either a guess or a historical figure from the retired 900-point HSAT scale.