Unweighted vs Weighted unifrac explanation

[Nicholas_Bokulich]

Hi @Stream_biofilm,

@Stream_biofilm

I’m just a little concerned about using read counts for abundance with the weighted test. I thought that was a “NO NO” in the Amplicon NGS world. Did that rule only apply to OTUs and not ASVs?

Nothing to worry about — sampling depth (read count) is normalized by even sampling prior to calculating beta diversity in the core-metrics actions, and other normalization strategies will be offered in the future.

This may remind you of another "no no" in the amplicon NGS world: the inadmissability of rarefying data prior to some analyses. But there is nothing to worry about here, either. UniFrac is not really negatively impacted by rarefying, and Unweighted Unifrac requires rarefying. See more discussion of this topic here.

I hope that helps!