Analogous to traditional significance testing, model fit is evaluated by calculating the difference between the Akaike Information Criterion (AIC) for best-fitting MiXeR estimates and a “reference” model. Positive AIC differences are interpreted as evidence that the best-fitting MiXeR estimates are distinguishable from the reference model. For univariate MiXeR, an “infinitesimal model” in which all variants are assumed to be ‘causal’ is used as the reference. For bivariate MiXeR, the best-fitting model is compared to minimum possible overlap and maximum possible overlap. We provide log-likelihood plots in figure S2 to visualise the parameter estimation procedure.
