In order to calculate the sample size that we will need, we discovered a Stata module called sampicc (https://ideas.repec.org/c/boc/bocode/s456978.html).

So we used it to calculate the sample size for an expected ICC of 0.6 and allowing for a variability among 0.45 and 0.75 (width: 0.15). We applied the sintaxis and we got the following result:

Code:

```
. sampicc 0.6 3, width(0.15) ci
****************************************************************
Sample Size for the Width of a Confidence Interval for ICC
****************************************************************
Given:
Expected Value (P1): 0.60
Number of Replicates: 3
CI level: 95%
Specified Width: 0.15
****************************************************************
Esimtated sample size is: 177
****************************************************************
```

Code:

```
. sampicc 0.8 3, width(0.15) ci
****************************************************************
Sample Size for the Width of a Confidence Interval for ICC
****************************************************************
Given:
Expected Value (P1): 0.80
Number of Replicates: 3
CI level: 95%
Specified Width: 0.15
****************************************************************
Esimtated sample size is: 63
****************************************************************
```

Does anyone know why we are getting this result? If we specify higher ICCs, we get smaller sample sizes.

Thanks in advance.