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really similar AIC

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valentinav's picture
Joined: 06/15/2020 - 08:45
really similar AIC

Hi All,
I run the ACE model and submodels, and the AIC are really similar.
ACE 2579
AE 2577.5
CE 2577.3
E 2584

Overall, I always get a difference of 1 between the AIC.
The best winning model is always coherent with the results of the correlation analysis, so I tend to trust it, however, the difference is really little.
Is there a way to establish what is a significant difference between AIC?

Thank you all!

AdminRobK's picture
Joined: 01/24/2014 - 12:15
confidence set

Have a look at omxAkaikeWeights().

Micanzach's picture
Joined: 10/05/2020 - 20:37
Formal test for AIC difference significance

To add to Valentina’s question, is there a correspondence between Akaike weights and p-value for AIC difference? In other words, is it the case that Akaike weight = .98 can be seen as AIC difference significant at p < .02? If this reasoning is incorrect, is there a way to calculate a p-value for AIC difference?

The reason I am asking this is because sometimes it is not possible to get a p-value when comparing models. For example, when comparing ACE and ADE models I do not get a p-value since the number of parameters is the same in both models.

Sometimes delta AIC > 2 is recommended as a rule of thumb, but perhaps there is a formal test for AIC difference significance.