Plots are very critical for diagnosing fit and any potential problems associated with a regression model. These four plots can help you identify observations which do not fit in neatly with the regression, and should be looked at individually to see if there is anything special about them. It is just a part of the iterative process which is a part of developing your model, and does not by itself indicate a bad model.
Run the basic plot for PainGLM. Note that we will plot the four plots in a 2x2 quadrant:
oldpar <- par(oma=c(0,0,3,0), mfrow=c(2,2)) plot(PainGLM) par(oldpar)