3.3 — Aligning Model Choice with Cost, Speed and Quality

CCAO-F Domain 3 · Task 3.3

What You Need to Know

Every choice between tiers spends three currencies: cost (usage allowance), time (wait per response), and depth (quality on demanding work). Name the currency a task needs, then pay only that.

Three Questions Name the Currency

1. What does being wrong cost here?
2. How many times will this run?
3. Who is waiting for the answer?

Volume Multiplies Cost and Speed

Run once, the tier difference is seconds and a sliver of allowance. Run five hundred times, it decides whether the job finishes today and whether the allowance survives the week. High-volume routine work belongs on the lighter tier with a sampled spot-check.

Stakes Multiply Quality

Some single outputs feed a consequential decision and need depth. The seconds a lighter tier saves are worthless against the cost of a subtly wrong conclusion. Quality requirements follow the cost of being wrong, not the prestige of the task. High-stakes output then goes to qualified human review, whatever model drafted it.

Split Mixed Workloads

Routine bulk → fast tier + sampled review. Hard core → capable tier + proper review. The model picker makes the split cheap.

Key Concept: Volume multiplies cost and speed; stakes multiply quality. When a stem mixes both shapes, the keyed answer almost always splits the workload.

Exam Traps

• Justifying the fast tier on a high-stakes output because it is “only one letter”
• Justifying the top tier on routine bulk because the work is important
• Escalating to a heavier model when the real defect is a vague brief