Hello,
I am using MaAsLin2 to examine the relationship between a categorical variable of mood (happy/neutral/not happy) and Shannon diversity. My Shannon diversity does not have any 0’s. The Shannon diversity range is 0.3 to 3.5, and the average is 2.2.
I am using the following code, adjusting for covariates:
fit_data = Maaslin2(
input_data = Shannon_diversity,
input_metadata = metadata,
output = “Adjusted Shannon Results”,
analysis_method = “LM”,
normalization = “CLR”,
transform = “NONE”,
standardize = TRUE,
min_prevalence = 0,
min_abundance = 0,
plot_heatmap = TRUE,
fixed_effects = c(“mood”, “Infant_ethnicity”, “infant_sex”),
reference = c(“mood,happy”, “Infant_ethnicity,Caucasian”, “infant_sex,Male”))
My issue is as follows: Shannon diversity is not normally distributed, so I am using CLR normalization. This does give me significant findings for mood, however the coefficients are exponentials (e.g. -5.9 e-17 ± 1.7 e-17, p = 0.0005, q = 0.01).
Can someone please advise why this may be, and whether this is correct or erroneous?