论文标题
符合截短和审查的对数正态分布的胜利力矩的方法
Method of Winsorized Moments for Robust Fitting of Truncated and Censored Lognormal Distributions
论文作者
论文摘要
在构建参数模型以预测未来索赔的成本时,必须考虑几个重要细节:(i)应设计模型以适应免赔额,政策限制和共同保险因素,(ii)应强估计参数,以控制异常值对模型预测的影响,以及(iii)所有积分预测的估计值,以及估计的所有点预测。本文提出的方法为同时解决所有这些方面提供了一个框架。使用每支付款和每笔付款变量付款,我们为截断和审查的lognortal分布的参数构建了Winsorized Momments(MWM)估计量的自适应版本。此外,该方法的渐近分布特性是得出的,并将其与最大似然估计量(MLE)和修剪矩(MTM)估计量的方法进行了比较。后者是MWM的主要竞争对手。此外,通过广泛的仿真研究和风险测量敏感性分析来验证理论结果。最后,使用经过充分研究的美国1500个赔偿损失的数据集说明了这些方法的实际性能。借助此真实的数据集,与专门用于截断和审查的样本数据的独立分布相比,复合模型的预测模型质量并不能太大改善预测模型的质量。
When constructing parametric models to predict the cost of future claims, several important details have to be taken into account: (i) models should be designed to accommodate deductibles, policy limits, and coinsurance factors, (ii) parameters should be estimated robustly to control the influence of outliers on model predictions, and (iii) all point predictions should be augmented with estimates of their uncertainty. The methodology proposed in this paper provides a framework for addressing all these aspects simultaneously. Using payment-per-payment and payment-per-loss variables, we construct the adaptive version of method of winsorized moments (MWM) estimators for the parameters of truncated and censored lognormal distribution. Further, the asymptotic distributional properties of this approach are derived and compared with those of the maximum likelihood estimator (MLE) and method of trimmed moments (MTM) estimators. The latter being a primary competitor to MWM. Moreover, the theoretical results are validated with extensive simulation studies and risk measure sensitivity analysis. Finally, practical performance of these methods is illustrated using the well-studied data set of 1500 U.S. indemnity losses. With this real data set, it is also demonstrated that the composite models do not provide much improvement in the quality of predictive models compared to a stand-alone fitted distribution specially for truncated and censored sample data.