ClarkLDF

class chainladder.ClarkLDF(growth: str = 'loglogistic', groupby=None)

An Estimator that allows for curve fitting development patterns according to Clark 2003.

The method fits incremental triangle amounts to one of “loglogistic” or “weibull” growth curves. Both of Clark’s methods, LDF and Cape Cod, can be estimated. To invoke the Cape Cod method, include “sample_weight” in when fitting the estimator.

Parameters:

growth: {‘loglogistic’, ‘weibull’}

The growth function to be used in curve fitting development patterns. Options are ‘loglogistic’ and ‘weibull’

groupby:

An option to group levels of the triangle index together for the purposes of estimating patterns. If omitted, each level of the triangle index will receive its own patterns.

Attributes:

ldf_: Triangle

The estimated loss development patterns.

cdf_: Triangle

The estimated cumulative development patterns.

incremental_fits_: Triangle

The fitted incrementals of the model.

theta_: DataFrame

Estimates of the theta parameter of the growth curve.

omega_: DataFrame

Estimates of the omega parameter of the growth curve.

elr_: DataFrame

The Expected Loss Ratio parameter. This only exists when a sample_weight is provided to the Estimator.

scale_: DataFrame

The scale parameter of the model.

norm_resid_: Triangle

The “Normalized” Residuals of the model according to Clark.

G_(age)

Growth function of the estimator.

Parameters:

ageint, float or array

The age(s) at which to compute the value of the growth curve.

Returns:

Triangle

A Triangle object with growth curve values

fit(X, y=None, sample_weight=None)

Fit the model with X.

Parameters:

XTriangle-like

Set of LDFs to which the munich adjustment will be applied.

yIgnored

sample_weightTriangle-like

Exposure vector used to invoke the Cape Cod method.

Returns:

selfobject

Returns the instance itself.

transform(X)

If X and self are of different shapes, align self to X, else return self.

Parameters:

XTriangle

The triangle to be transformed

Returns:

X_newNew triangle with transformed attributes.

Inherited Methods

ClarkLDF.fit_transform	Fit to data, then transform it.
ClarkLDF.get_metadata_routing	Get metadata routing of this object.
ClarkLDF.get_params	Get parameters for this estimator.
ClarkLDF.pipe
ClarkLDF.set_backend	Converts triangle array_backend.
ClarkLDF.set_output	Set output container.
ClarkLDF.set_params	Set the parameters of this estimator.
ClarkLDF.to_json	Serializes triangle object to json format
ClarkLDF.to_pickle	Serializes triangle object to pickle.