# Variance Inflation Factor (VIF).

The variance inflation factor (VIF) is a measure of the amount of variability in a statistic that can be attributed to inter-correlations among variables in a dataset.

In general, the higher the VIF, the greater the amount of variance that can be attributed to inter-correlations among variables, and the less reliable the statistic.

VIF is typically used in multiple regression analysis to assess the degree of collinearity among predictor variables.

A VIF of 1 indicates that there is no collinearity among the predictor variables; a VIF greater than 1 indicates that there is collinearity among the predictor variables.

The VIF can be calculated for each predictor variable in a multiple regression model.

A VIF of 1.5 or greater indicates that the predictor variable is moderately correlated with the other predictor variables in the model, and a VIF of 2 or greater indicates that the predictor variable is highly correlated with the other predictor variables in the model. Why is multicollinearity a problem? Multicollinearity is a problem because it can lead to inaccurate or imprecise estimates of the coefficients of the variables in a regression model. This is because multicollinearity can cause the variables to be linearly dependent on each other, which can lead to problems with the model's ability to accurately estimate the effect of each variable on the dependent variable.

#### What does high VIF mean?

When two or more variables are highly correlated, it means that they are measuring the same thing. This is a problem because it means that the variables are not providing any new information, and it can lead to issues with overfitting.

A high VIF indicates that there is a strong correlation between the variable and the other variables in the model. This means that the variable is not providing any new information and is just a duplicate of the other variables. This can lead to issues with overfitting, because the model will be relying on the same information over and over again.

#### What is VIF and tolerance?

VIF, or the variance inflation factor, is a measure of the amount of collinearity between independent variables in a multiple regression model. The tolerance is the inverse of the VIF, and can be used to assess the degree to which each independent variable is affected by collinearity. A high VIF indicates that collinearity is a problem, while a low tolerance indicates that a variable is highly affected by collinearity.

### What is the range of VIF?

A Variance Inflation Factor (VIF) is a measure of the amount of variance in a predictor that can be attributed to collinearity with other predictors within a model. In other words, it quantifies how much the variance of a predictor is "inflated" by its correlation with other predictors.

The range of VIF is from 1 to infinity. A VIF of 1 indicates that there is no collinearity between the predictor and other predictors in the model. A VIF greater than 1 indicates that there is collinearity between the predictor and other predictors in the model. The amount of inflation is proportional to the VIF value. For example, a VIF of 2 indicates that the variance of the predictor is doubled due to collinearity. How do I calculate VIF in Excel? In Excel, VIF can be calculated using the "Data Analysis" tool. To do this, first select the data that you want to include in the VIF calculation. Then, click on the "Data" tab and select "Data Analysis." In the "Data Analysis" dialog box, select "Regression" and click "OK."

In the "Regression" dialog box, select the variable that you want to use as the dependent variable and click "OK."

The VIF for the selected dependent variable will be displayed in the output.