Study guide: Design and Test a Purpose-Limited Log
Minimize collected fields, aggregate fictional events, test deletion and examine release risks.
Ideas to explain in your own words
- Match a data collection design to a limited operational purpose.
- Build daily failure counts from fictional records and drop unnecessary fields.
- Test a retention boundary using a fictional day counter.
- Apply an exercise release policy and recognize a subtraction disclosure.
Watch your reasoning
- Aggregate counts match the limited operational question and avoid unnecessary identifying fields. Access and retention controls still matter, and removing names alone does not make free-text answers safe to publish.
- The new pass does not increment D2 A. The new fail creates D2 B with count 1, so both D2 groups have count 1.
- 12 − 5 = 7, and the inclusive rule deletes at age 7 or greater.
- n = 5 satisfies at least 5, and approval is true, so this exercise outputs the failure count 2. Passing this rule does not certify anonymity.
A worked review example
Design a useful log with less personal data: An aggregate row such as date = fictional Day 1, activity_code = algebra-01, failures = 7 serves the count purpose without names, email, addresses or answer text. The design still needs review before publishing small-group counts. Aggregate Only the Required Events: Aggregate output: (D1,A,2), (D1,B,1), (D2,A,1). Four fail events are counted and one pass event is ignored. No person identifiers or answer text are retained in the exercise output. Apply a Stated Deletion Schedule: At current day 10: row day 2 has age 8 → delete; day 3 age 7 → delete; day 4 age 6 → keep; day 10 age 0 → keep. Day 11 is invalid, not a negative-age row to retain. Test a Bounded Aggregate Release Rule: A passes both checks, so release 3. B fails the size check; C fails the review flag. Publishing total A+B = 4 alongside A = 3 reveals B = 4 − 3 = 1 despite withholding its cell. The example needs review of related releases, not just each cell alone.
Make a practice plan
- Try the supplied lesson problems without looking at the answers.
- Compare your method with the worked examples and explain any correction.
- Use the new review cases, then complete the transfer task on paper or in your own document.