关于R语言MuMIn包get.models函数subset参数取值含义的技术咨询

Hey there, let's clear up this confusion around the subset argument in get.models()—it's simpler than it might seem at first!

When you run dredge() (like you did with dd.ITD.2018.slope <- dredge(fm.2018.ITD)), the resulting object is a sorted table of all candidate models, ordered by their fit quality (by default, from best to worst using AICc).

Here's what those numeric subset values mean:

• subset = 1: Grabs the top-ranked (best-fitting) model from the sorted dredge table
• subset = 2: Grabs the second-ranked model (the next best fit after the top one)
• subset = 3: Grabs the third-ranked model

The [[1]] you see at the end (like in get.models(..., subset = 2)[[1]]) is just extracting the actual model object from the list that get.models() returns. Even if you only request one model, get.models() outputs a list, so [[1]] pulls out the single model from that list for you to use with summary() or other functions.

To double-check this, you can print the top few rows of your dredge output to match the rankings:

# View the top 3 models in your sorted dredge table
head(dd.ITD.2018.slope, 3)

Each row in this output corresponds directly to the subset number—row 1 = subset=1, row 2 = subset=2, etc.

One quick note: If you filter your dredge table (e.g., subset(dd.ITD.2018.slope, delta < 2)), the ranking resets based on that filtered subset. So if you ran get.models() on this filtered table, subset=1 would be the top model in the delta < 2 group, not the original full dredge table.

内容的提问来源于stack exchange，提问作者Evie McCloughan