How it works
An equal or representative average cluster size and intraclass correlation give the approximate design effect 1+(m−1)rho. This form solves for average cluster size; enter the known quantities in Approximate design effect, Intraclass correlation.
Inputs and units
| Input | Example value | What to enter |
|---|---|---|
| Approximate design effect | 1.45 x | Formula symbol: effect. Required unit: x. Must be greater than zero. |
| Intraclass correlation | 0.05 | Formula symbol: rho. Enter a numeric value. Use a non-negative value. Allowed range: 0–1. |
Worked example
Show example inputs and results
This example is generated by the same calculation engine using the starting values in the form. Your own inputs produce your own result.
- Approximate design effect
- 1.45 x
- Intraclass correlation
- 0.05
Complete example results
- Average cluster size
- 10
Reading the result
The result solves for average cluster size from the entered quantities. Check the result unit and the formula conditions before using it.
Questions and answers
Can I use the example values for my own calculation?
The example values illustrate the calculation. Replace every input with your own information, especially dates, rates and the selected operation.
When can I use the average cluster size result?
Enter rho as a decimal: 0.10 means 10%. This approximation uses an equal-cluster design; weighting, multistage and variable-cluster effects are excluded.
Why are some results rounded?
Results display up to 8 decimal places. Calculations use the unrounded values; very small values use scientific notation. JavaScript floating-point arithmetic can introduce tiny rounding differences.
Are my inputs sent to a server?
The calculator processes inputs in your browser. Its code does not send your values to a server.
Method sources: unstats.un.org