---
name: uchicago-data-analytics-cohort-segmentation
description: Cohort and segmentation analysis playbook. Use for cohorts, retention, churn, conversion, lifecycle stages, entering classes, patient/student/customer groups, segment comparisons, funnel stages, and longitudinal group tracking.
---

# Cohort And Segmentation

## Purpose

Make groups comparable and prevent cohort leakage, double counting, and
misleading segment comparisons.

## Cohort Definition

Confirm:

```text
Cohort entry event:
Cohort entry date/period:
Population:
Exclusions:
Follow-up window:
Outcome metric:
Comparison cohort:
Segment dimensions:
```

## Checks

- A person/entity belongs to one cohort unless explicitly allowed.
- Entry criteria are stable across periods.
- Follow-up windows are comparable.
- Suppressed/small cells are handled.
- Segment totals reconcile to overall counts when appropriate.

## Output

Use a table or chart that clearly shows:

- cohort size
- outcome by period
- retention/conversion/drop-off rate when applicable
- segment differences
- caveats about partial periods or incomplete follow-up

Offer to save cohort definitions to `DEFINITIONS.md`.