# Null & Residual Deviance in GLM in R

For a GLM in R, is it correct to interpret that Higher the difference between NULL & RESIDUAL deviance, better is your model? If not, then how do i know if my model is good or bad (for GLM - poisson, gamma, tweedie)

Simply check your model using anova.glm() with a F test or a Chi-squared test. If your write anova(model,test="F") this will automatically compare it to a null model and send back a p-value. Check Zuur et al. 2009 and, in R, ?anova.glm