# Backward elimination of model terms in logistf models

### Description

These functions provide simple backward elimination/forward selection procedures for logistf models

### Usage

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### Arguments

`object` |
A fitted logistf model object. To start with an empty model, create a model fit with a formula=<y>~1, pl=FALSE. (Replace <y> by your response variable.) |

`scope` |
The scope of variables to add/drop from the model. If left blank, |

`steps` |
The number of forward selection/backward elimination steps. |

`slstay` |
For |

`slentry` |
For |

`trace` |
If TRUE, protocols selection steps. |

`printwork` |
If TRUE, prints each working model that is visited by the selection procedure. |

`pl` |
For |

`...` |
Further arguments to be passed to methods. |

### Details

The variable selection is simply performed by repeatedly calling add1 or drop1 methods for logistf, and is based on penalized likelihood ratio test. It can also properly handle variables that were defined as factors in the original data set.

### Value

An updated logistf fit with the finally selected model.

### Author(s)

Georg Heinze

### Examples

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