Five signals your data are clustered
Shared sites, teams, people, households, and time points can make ordinary independence assumptions misleading.
Shared sites, teams, people, households, and time points can make ordinary independence assumptions misleading.
Look for shared context
Observations from the same school, clinic, household, team, or participant often share unmeasured influences.
Look for repeated measurement or sampling stages
Time points within a person and units selected through groups both create dependence, though the appropriate model may differ.
Decide what level the question concerns
Within-cluster and between-cluster associations are not interchangeable. Coding, centering, and random effects should follow that distinction.
Failure modes to check
- Choosing a method because it is familiar rather than because it matches the estimand and data structure.
- Treating assumptions as a generic pass/fail checklist instead of evidence about a specific model.
- Changing the workflow after seeing results without recording the decision or its effect on uncertainty.
- Reporting software output without tracing the claim to final code, diagnostics, and limitations.
Continue the decision path
Explore the related statistical consulting service, or discuss the decision in your own study.
Related decision guides
Methodological note
This guide provides general educational information. The appropriate decision depends on the study question, design, data, evidence, ethics, and institutional requirements.