Timeline for Interpreting plot of residuals vs. fitted values from Poisson regression
Current License: CC BY-SA 3.0
9 events
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| Sep 19, 2016 at 12:26 | history | edited | whuber♦ | CC BY-SA 3.0 |
added 5 characters in body
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| Aug 11, 2016 at 13:25 | comment | added | Meg | @whuber - thanks, but I don't see any discussion of Poisson regression in this text. | |
| Aug 11, 2016 at 12:43 | comment | added | whuber♦ | @Meg Hosmer & Lemeshow, Applied Logistic Regression, include a section on diagnostic plots. | |
| Aug 11, 2016 at 0:16 | comment | added | Meg | 2/2: Do you have a go-to reference that discusses POI residuals more thoroughly by any chance? | |
| Aug 11, 2016 at 0:15 | comment | added | Meg | 1/2: Thanks @whuber. I understand for this answer the model is known to be correct since the data were simulated from a given distribution, but in practice it's unknown (as in the OP's post). Also, what I wrote about residuals does apply to POI regression (not all GLMs, no, but this one) - the reference I gave was discussing POI regression specifically. I've only seen texts show standardized POI residuals (Pearson or deviance, e.g.) centered about y = 0, so I'm not sure what I should be looking for, because for this model (which is obviously correct), the plot looks nothing like that. | |
| Aug 10, 2016 at 22:12 | comment | added | whuber♦ | @Meg That advice doesn't directly apply to residuals of a GLM. Note that the model used to illustrate this answer is known to be correct because it's the one used to generate the data. | |
| Aug 10, 2016 at 20:37 | comment | added | Meg | So is the above plot concerning? Texts (Statistical Modeling for Biomedical Researchers: A Simple Introduction to the Analysis of Complex Data, Dupont, 2002, p. 316, e.g.) indicate the fitted vs. residual plot should be centered about the zero residual line, and either fan (if raw residuals) or not (if deviance, e.g.). With a limited range of counts in the outcome variable, you get these bands, and, as in the above plot, they're not centered about the line at y = 0. How do we know the OP's residual plot (or the example plot made in this answer) indicates the model is fitting the data well? | |
| Jun 11, 2012 at 23:11 | comment | added | cardinal | (+1) The color goes a long way in showing what is happening. | |
| Jun 11, 2012 at 20:52 | history | answered | whuber♦ | CC BY-SA 3.0 |