ANCOM results: ASV with W values of 0 identified as differentially abundant

[colinbrislawn (Colin J Brislawn)]

Good morning,

But the w value are very low even =0

You may have found this already, but if not, check out this thread on ANCOM (1) and low W values:

ANCOM: 'low W taxa identified as significant' issue's workaround, ANCOM2 code/instructions

Hi folks, Some users (including myself) have noticed that in some cases ANCOM behaves oddly in that it identifies very low/0 W valued taxa as differentially abundant. See here and here for example of this behavior. In contacting one of the developer's of ANCOM regarding this issue ,Dr. Peddada had the following explanation/recommendation. A potential reason for the problem is that the earlier code was trying to empirically derive the threshold for significance. When W takes on small values …

Also check out the ANCOM-BC plugin for Qiime2:
https://github.com/mortonjt/q2-ancombc