**Hi, community！I found a question when practicing R.**

Is the **interaction term** counted **as an independent variable** in a multiple linear regression analysis,with the other predictor variables are required to all be non-collinear? It is found that when an interaction term is added, there is 100% covariance with the other terms.

Is the Variance Inflation Factor (VIF) calculation in the presence of an interaction term the same as in the absence of an interaction term?

Maybe like this

```
model1<-lm(Sepal.Length~Sepal.Width*Petal.Length*Petal.Width,iris)
vif(model1)
```

**Any help would be appreciated.**