# Thread: When Logistic Regression Coefficient Increases

1. ## When Logistic Regression Coefficient Increases

Hi All,

I am trying to understand the relationship between naturalization (whether someone becomes a naturalized citizen or not), using data from the American Community Survey.

My dependent variable: Naturalization (non-citizen vs. naturalized-citizen).
My independent variables: educational attainment (x1), sex (x2), and age (x3).

Model 1: y = x1;
Model 2: y = x1 + x2 + x3;

Here is the problem. From model 1 to model 2, the odds ratio of x1 increases from 1.1 to 1.7. I was expecting the odds ratio of x1 to decrease by adding x2 and x3.

My question is, what does it mean when the odds ratio of x1 increases after adding additional predictors to the model? Any advice would be greatly appreciated. Thanks!

2. ## Re: When Logistic Regression Coefficient Increases

It means there was some redundancy ("multicollinearity") between x1 and your other predictors x2 and x3. The effect of x1 in model 1 was being "suppressed" due to being either positively related to a predictor that has a negative association with the DV, or negatively related to a predictor that has a positive association with the DV, or some combination of both.

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