Hi @martinctc, First welcome to the community.

You say that you post the same issue on stack. Can u link it here? See the doc in the faq about cross-post

Now your question. The VarImp here is the sum of absolute value of coef of a variable.

```
# library(tidyverse)
library(nnet)
library(caret)
#> Le chargement a nécessité le package : lattice
#> Le chargement a nécessité le package : ggplot2
fit <- multinom(Species ~ ., data = iris) # fit model
#> # weights: 18 (10 variable)
#> initial value 164.791843
#> iter 10 value 16.177348
#> iter 20 value 7.111438
#> iter 30 value 6.182999
#> iter 40 value 5.984028
#> iter 50 value 5.961278
#> iter 60 value 5.954900
#> iter 70 value 5.951851
#> iter 80 value 5.950343
#> iter 90 value 5.949904
#> iter 100 value 5.949867
#> final value 5.949867
#> stopped after 100 iterations
fit
#> Call:
#> multinom(formula = Species ~ ., data = iris)
#>
#> Coefficients:
#> (Intercept) Sepal.Length Sepal.Width Petal.Length Petal.Width
#> versicolor 18.69037 -5.458424 -8.707401 14.24477 -3.097684
#> virginica -23.83628 -7.923634 -15.370769 23.65978 15.135301
#>
#> Residual Deviance: 11.89973
#> AIC: 31.89973
```

^{Created on 2020-02-27 by the reprex package (v0.2.1)}

For instance:

For `Sepal.length`

his importance ( `13.38206`

) is the sum of `abs(-5.458424)`

and `abs(-7.923634)`

.

Hope it help