Cluster Sample Size Calculator (ICC)

How many clusters to sample when respondents arrive in groups: the design effect from the intraclass correlation, worked step by step with your own numbers.

Population size

Number of clusters available

Intraclass correlation (ICC)

Target margin of error

Confidence level

Expected response rate

Calculating…

Design effect vs. intraclass correlation at your average cluster size. Small ICC moves explode the required sample; the marker shows your ICC.

Assumption check

For cluster designs (schools, clinics, neighborhoods). The intraclass correlation drives the design effect, and the design effect drives everything.

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