Posts Tagged ‘ Firth logistic regression ’

Example 9.24: Changing the parameterization for categorical predictors

March 22, 2012
By
Example 9.24: Changing the parameterization for categorical predictors

In our book, we discuss the important question of how to assign different parameterizations to categorical variables when fitting models (section 3.1.3). We show code in R for use in the lm() function, as follows:lm(y ~ x, contrasts=list(x,"contr.trea...

Read more »

Example 8.15: Firth logistic regression

November 22, 2010
By
Example 8.15: Firth logistic regression

In logistic regression, when the outcome has low (or high) prevalence, or when there are several interacted categorical predictors, it can happen that for some combination of the predictors, all the observations have the same event status. A similar e...

Read more »