This method assumes that the assay results to be combined are independent but are heterogeneous, that is there is significant variability in the assay results arising from different laboratory conditions.
Given Relative Potency results to combine, with variances of the logarithms of the Relative Potency results, the inter-assay variation is calculated as
where is the mean of the logarithm of the Relative Potencies.
The logarithm of the Combined Relative Potency is then estimated as the weighted mean of the logarithms of the Relative Potencies from the individual studies:
where the weights are calculated as
The logarithm of the confidence interval is estimated, regardless of whether the assays are continuous or quantal, as
