Hi,(adsbygoogle = window.adsbygoogle || []).push({});

I would like to exponentiate the values of independent variables in a regression model, possibly using splines. I know that collinearity between X and X^2 is to be expected and the standard remedy is to center by taking X-average(X) prior to exponetiating. This seems odd to me because it will change the shape of the relationship between X and X^2 to one that is U-shaped, not monotonic. For example, if after centering you have

-2

-1

0

1

2

then the formerly lowest value will now be equal to the highest when squared. This seems to disrupt the idea that lower values have a lesser effect, lets say. What am I not getting that makes this make sense to do? Thanks. Seth

**Physics Forums | Science Articles, Homework Help, Discussion**

Join Physics Forums Today!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

# Centering to reduce collinearity of x^2?

**Physics Forums | Science Articles, Homework Help, Discussion**