ANCOM-BC interpreting results

I can successfully run ANCOM-BC but am still confused about results interpretation, specifically LFC.

I know that the github page answered the primary results for LFC (question 3) but I am still struggling to understand.

  1. Q: In the primary results, what do lfc_(Intercept), lfc_groupB, and lfc_groupC represent if I have a group variable with categories A, B, and C?
    A: In the primary results, the terms lfc_groupB and lfc_groupC represent the log fold changes (logFC) relative to the reference group, which is group A by default. These logFC values indicate the difference in abundance between group B and group A, and between group C and group A, respectively.
    On the other hand, lfc_(Intercept) refers to the log fold change of the grand mean, which may not be a parameter of particular interest in this context.
    It's worth mentioning that if you wish to change the reference group, you can use the factor function in R to rearrange the levels of the group variable accordingly.

If I am looking at lfc_groupB, this is the difference between group B and group A where group A is the reference group. So does a positive LFC indicate increased abundance in group A and negative LFC indicate decreased abundance in group A; another way of saying it is positive LFC is discriminatory for group A while negative LFC is discriminatory for group B?


If you are comparing group B to control A, positive lfc values will indicate features more abundant in group B and negative values for more abundant in control.

A                       B
             ++++++++++ F1
F2 ----------


1 Like

Thanks for the help!

This topic was automatically closed 31 days after the last reply. New replies are no longer allowed.