Logistic Regression

Lead Author(s): Jeff Martin, MD

Definition of Logistic Regression

Logistic regression is the method of multivariable analysis used most often in cross-sectional and case-control studies.

In logistic regression the log odds of the outcome is modeled with the linear equation:


Log odds (called the logit, hence logistic regression) are used because Prediction in a linear model isn’t constrained to a 0 minimum or a 1 maximum, So exponentiating the b from a logistic equation returns an odds for one unit of change in the variable x.