Timeline for Comparing nested GLMs via chi-squared and loglikelihood
Current License: CC BY-SA 3.0
8 events
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| Sep 25, 2013 at 14:06 | comment | added | Torvon | Last question: usually in my analyses the DF are 8 smaller in the more constrained model. In this particular case above, using the code you suggested, "residual df" of the freely estimated model m1 is 8 smaller than the constrained model m2 (12339 vs. 12347), although the fit is much better for m1 (deviance: 9693 vs 10945). How can that be? Thank you! | |
| Sep 23, 2013 at 14:31 | comment | added | Ben Bolker | If you are working in a GLM(M) context then "chi-square" and "deviance" are synonymous as far as I can tell (but as I pointed out "deviance" is more precise). | |
| Sep 23, 2013 at 14:28 | comment | added | Torvon | Thank you again. Although deviances are compared, is this a "chi-square difference test"? Would you know of any example where such a model is reported in a paper? I'm used to reporting chi-square, df, AIC (rmsea etc.), chi-square-diff and df-diff, and p. Not sure what to report in this case above. Thank you! | |
| Sep 12, 2013 at 14:00 | vote | accept | Torvon | ||
| Sep 12, 2013 at 13:18 | comment | added | Ben Bolker | You can report them as chi-square values, but it would generally be more informative to report them as deviances; there are lots of different statistics that are chi-square distributed | |
| Sep 12, 2013 at 11:47 | comment | added | Torvon | Ben, thank you for this very helpful comment! You are right, I confused CLM and GLM -- I am using GLMs now, and get the output you describe above. Residual Deviances in my case are M1=9693 (resid. DF=12339) and M2=10945 (resid. DF=12347) (Deviance=-1252) with DF_diff=-8 (p<0.001). Does that mean I can report these two values as chi-square values in a paper, or would that be incorrect? | |
| Sep 11, 2013 at 19:03 | history | edited | Ben Bolker | CC BY-SA 3.0 |
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| Sep 11, 2013 at 17:20 | history | answered | Ben Bolker | CC BY-SA 3.0 |