Erratum to: Sample size calculations for cluster randomised controlled trials with a fixed number of clusters

Erratum

After publication of the original article [1], it came to the authors’ attention that there was a typing error in equation 16. There should be a rho on the denominator of this equation.

The published version of equation 16 is:

$$ m=\frac{\left(1-\rho \right){n}_{I\ }}{k-{n}_I\left(c{v}^2+1\right)} $$

The correct version of equation 16 is:

$$ m=\frac{\left(1-\rho \right){n}_{I\ }}{k-{n}_I\left(c{v}^2+1\right)\rho } $$