Spearman
\[D_{Spearman} = 1 - \frac{6 \sum_{j=1}^{S_T} \left ( rank(S_{Aj}) - rank(S_{Bj}) \right )^2} {S_T (S^2_T-1)}\]- where \(rank(S_{Aj})\) is the number of OTUs in sample A with higher or equal abundance to \(S_{Aj}\).
- where \(rank(S_{Bj})\) is the number of OTUs in sample B with higher or equal abundance to \(S_{Bj}\).
- where S_T is the total number of OTUs.