What is a good variance inflation factor?
What is known is that the more your VIF increases, the less reliable your regression results are going to be. In general, a VIF above 10 indicates high correlation and is cause for concern. Some authors suggest a more conservative level of 2.5 or above.
What does VIF of 1 mean?
A VIF of 1 means that there is no correlation among the jth predictor and the remaining predictor variables, and hence the variance of bj is not inflated at all.
What is the minimum value of VIF?
1
If Rj equals zero (i.e., no correlation between Xj and the remaining independent variables), then VIFj equals 1. This is the minimum value.
What do you do if VIF is bigger than 5?
If multicollinearity is a problem in your model — if the VIF for a factor is near or above 5 — the solution may be relatively simple. Try one of these: Remove highly correlated predictors from the model. If you have two or more factors with a high VIF, remove one from the model.
Why VIF should be less than 10?
The variance inflating factor (VIF) is used to prove that the regressors do not correlate among each other. If VIF>10, there is collinearity and you cannot go for regression analysis. If it is <10, there is not collinearity and is acceptable.
Is VIF less than 10 acceptable?
Small VIF values, VIF < 3, indicate low correlation among variables under ideal conditions. The default VIF cutoff value is 5; only variables with a VIF less than 5 will be included in the model. However, note that many sources say that a VIF of less than 10 is acceptable.
What is a bad VIF score?
But, a VIF value of 14 is generally considered problematic. Multicollinearity occurs when two or more predictors in the model are correlated and provide redundant information about the response. Multicollinearity was measured by variance inflation factors (VIF) and tolerance.
What is acceptable VIF for multicollinearity?
Generally, a VIF above 4 or tolerance below 0.25 indicates that multicollinearity might exist, and further investigation is required. When VIF is higher than 10 or tolerance is lower than 0.1, there is significant multicollinearity that needs to be corrected.