Why this is mistaken
Define the target population, then reconcile the accessible frame to it. Missing, duplicated, late-posted, archived, or ineligible units can make a random sample precisely representative of the wrong list.
Where to watch
When this mistake may appear
- A source-system export is labeled complete.
- Selection is random within an untested query result.
Check your work
Your work may contain this mistake if:
- Skips coverage, duplicate, eligibility, and cutoff reconciliation.
- Calls an accessible list the population without defining the target first.