Binning
Binning is the process of transforming a continuous variable into either a categorical variable or a set of discrete indicator variables.
Contents
Usage
In Modeling
There is significant discussion surrounding the use of binning in regression models.
If the intention of binning is to capture non-linearity, then a non-linear model is generally preferable. Another common solution to that problem is to regress on a variable and the square of that variable.
Gelman discusses the approach partly in Regression and Other Stories and in blog posts: "One thing that people don't always realize is that you can do binning and linear together, for example in R, y ~ z + age + age.65.74 + age75.84 + age.85.up" [link and styling mine].