This package contains R functions for two stage bootstrap simulations and loss triangle manipulations. The detail bootstrapping theory can be found in "Analytic and bootstrap estimates of prediction errors in claims reserving" from Peter England and Richard Verrall. The package contains various loss reserve triangle manipulations, including LDF, Weighted Average, etc. For detail implementations, please see the help pages below.

Here are simple steps to perform bootstrap simulation:

1. Download and install the "bootstrap" package, run R, and load the "bootstrap" package. 2. (optional) Prepare a paid loss triangle (download example) and save it in a .csv file, so that the R can read it. Make sure triangle has years and ages. 3. Run function bootstrap.load(), to load the triangle from the file dialog window 4. Run function bootstrap.start(round=1000, percentile=TRUE) to start the simulation in 1000 rounds. Try 100 first... Results are presented either by a matrix of percentile format (if percentile=TRUE), or a matrix of reserves (percentile=FALSE)

Accumulate | Accumulate an incremental triangle |

add | Add two triangles |

bootstrap | What the package does: This package will contain functions for two stage bootstrap simulation and loss triangle manipulations |

bootstrap.load | Load accumulated paid loss triangle and initialize the bootstrap object |

bootstrap.start | Start the two stages of bootstrap simulation |

ChiSqr | get the Chi Square (residual ^2) in preparing the bootstrap object |

count | Count the triangle cells |

develop | Fill the lower part of the triangle, using LDF from weighted average. |

fit | Get the fitted cumulative loss triangle |

GammaTrial | Do gamma simulation on incremental development triangle |

getAges | Get triangle ages |

getDiagnal | Get triangle cumulative data |

getFittedIncrementalLoss | Get Fitted Incremental Loss triangle for bootstrap object |

getLDF | Get the LDF from triangle, using weighted average. |

getReserveFromLDF | Calculate reserves from the weighted average LDF selection only |

getResidual | Get the residual of bootstrap object |

getScale | Get the scale of the gamma distribution from bootstrap object |

getWeightedAvg | Get weighted average of a triangle |

getYears | Get triangle years |

Incremental | Increment an accumulated triangle |

minus | Triangle A - Triangle B |

Pretty print a triangle object | |

readcsvfile | Read a triangle object from csv file. |

residual | Calculate the residual triangle. r= (A-E)/E^.5 |

sample | Sample with replacement--core bootstrap concept. |

Simulate | 2 stages of the bootstrap simulation |

Sudo | Get the "whatif" triangle after the first stage bootstraping simulation |

summary | Pretty summary a triangle object |