In the version dated "2019-06-21" in section 2.3, there's a typo where "model complex model" should just be "complex model."
The simple model, analogous to the statistical “null model” contains only an intercept term while the model complex model has a single term for an individual predictor from the risk set.
In the version dated "2019-06-21" in section 2.3, there's a typo where "model complex model" should just be "complex model."