Post #3266145

Relative abundance went up 30%. Which part moved — focal species increased, or everything else decreased? A ratio collapses two biological processes into one number. Can't tell which drove it. numdenom fits numerator and denominator as a joint model with shared random effects. Sites that are good for the focal species tend to be good overall — the model captures that correlation instead of collapsing it. The ratio becomes interpretable again. #rstats