Unit 3 · Programming 2 · Lesson 3.21 · Practice PT

How the Create PT Actually Works

Week 5 is a full dress rehearsal of the Create Performance Task — the real thing, in miniature. Today: what it actually requires, how it’s scored, and the one decision that makes or breaks it — picking an idea small enough to finish.

Big Idea 3 — Algorithms & ProgrammingPractice PT #1 · graded gently
Verify against the current CED before you rely on this. The Create PT’s exact requirements and the written-response format have changed before. This page reflects the recent structure; always cross-check the College Board’s current Student Handouts and scoring guidelines for your exam year.
1

Where We Are

People→ Bits→ Programs→ Internet→ Security→ Big Data→ Impact

Still in Programs, the last week of the unit. You have every skill the PT needs — lists, a procedure with a parameter, selection, iteration (3.14 was the exact shape). This week you assemble them into a program that’s yours, under real PT conditions, while the stakes are still low.

2

The Hook

The PT isn’t a harder program. It’s a smaller one, explained well. Students lose points not because their code is too simple, but because they picked something too big, ran out of time, and couldn’t explain what they built.

The winning move is scope control: a modest program that clearly contains the required pieces, plus written responses that name those pieces precisely. You already wrote the required shape in 3.14. This week is about doing it deliberately and describing it in the exam’s language.

3

The Four Code Requirements

Your program must clearly contain all four of these. Every one is something you built in this unit:

Your program needs

□ A list (or other collection) used to manage complexity — storing data you actually use. (3.6–3.7)

□ A student-developed procedure with at least one parameter that affects what it does. (3.12)

□ Selection and iteration inside that procedure — an if and a loop doing real work. (2.12–2.13, 3.1–3.8)

□ A call to that procedure from your program, using its result. (3.11, 3.14)

That is — word for word — count_above(scores, cutoff) from 3.14, called from a main program. If you can build that, you can meet the code requirements.

Plus two written responses. Beyond the code, you write short responses about your program: what it does and its purpose, how your procedure works, and how you developed and tested it. Those are graded in the same “name the parameter, the selection, the iteration, the return” language you’ve practiced since 3.15.
4

How It’s Scored

The scoring guidelines award points for specific, checkable things — not for how impressive the program looks. Roughly, points come from:

Program runs and has a clear purpose you can state✓
A list used to manage complexity (and you explain how)✓
A student-developed procedure with a parameter that changes its behavior✓
Selection and iteration inside that procedure, doing real work✓
A call to the procedure, and written responses that describe it accurately✓

Notice what earns nothing: cleverness, length, or features you can’t explain. A short program that hits every row and is described precisely outscores an ambitious one that doesn’t — every time.

5

A Strong Idea vs a Weak One

Too big / risky

“A multiplayer game with graphics and accounts.” You’ll spend all three days fighting features, the required pieces will be buried or missing, and you won’t be able to point cleanly to your procedure. Ambition, no points.

Scoped to win

“A quiz-score analyzer: store scores in a list, and a procedure grade_summary(scores, cutoff) that loops through them, counts how many passed, and returns a summary.” Small, finishable, and every required piece is obvious and explainable.
A good PT idea is one you can describe in a single sentence that already names a list and a procedure with a parameter. If your one-sentence pitch doesn’t contain those words, shrink the idea until it does.
6

Today’s Task — Get Your Idea Approved

Before you write any code, you must get your idea approved. Use this self-check first — if you can’t fill every blank, your idea isn’t scoped yet.

Check each box you can honestly fill in.

When all six are checked, write your one-sentence purpose and show it to your teacher for approval. Scope control is the whole job this week — a green light today is worth more than any amount of coding.

7

Impact Check

“Scope” is a real-world superpower

Every professional project fails the same way the over-ambitious PT does: too much promised, not enough finished, nobody able to explain what shipped. Learning to cut an idea down to something you can actually complete and describe — a “minimum viable product” — is exactly how real software gets built. The PT is training a habit that outlasts the exam by decades.

8

Connections

Came from 3.14 — the required code shape is exactly the procedure-with-a-list you already built.
Next in 3.22–3.24 — three build days: write your program and capture your Personalized Project Reference.
Then 3.25 — the timed written responses about your own program.
Returns for real — this is the actual Create PT you’ll do for the exam. Practicing it now, graded gently, is the point.
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