Interpret ANCOM test and the percentile table


I have samples from a controlled environment including control and treatment groups, so the membership of the microbiome is limited (low diversity). When applying ANCOM, I got only one feature of significant differential abundance (W = 19, clr = -2.2).
In the percentile table:
Control: the 5 values (0, 25, 50, 75, 100%) were 1 for each
Treatment: first 3 values were 1, and 38, 152 for 75%, 100% respectively.
When applying the interpretation mentioned here, to the given results in my percentile table, it does not make sense to me since the values of significant feature is higher in the treatment compared to the control. However, the frequency of this taxon is dramatically decreased upon treatment when looking at either the feature table/its calculated relative abundance. I understand that low values in the percentile table should be assigned to the treatment group, not the control group because the feature abundance decreased by the treatment. Do I understand it right?
I hope I have explained my question well!


1 Like

Hi @Eman,

Thanks for reaching out! This is certainly interesting. Can you provide the exact command/parameters you used when running ancom? And the resultant visualization, if you don't mind sharing?

Cheers :lizard:

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