I am running a generalized linear model with Gamma distribution in R (glm, family=gamma) for my data (gene expression as response variable and few predictors). I want to calculate r-squared for this model.
I have been reading about it online and found there are multiple formulas for calculating $R^2$ (psuedo) for glm (in R) with Gaussian (r2 from linear model), logistic regression (1-deviance/null deviance), Poisson distribution (using pR2 in the
pscl package, D-squared value from the
modEvA R package). But I could not find anything specific to Gamma distributions.
modEVA packages be used for the Gamma distribution as well, or is there any other formula for doing the same?