This project implements fundamental claims reserving methods from Stochastic Claims Reserving Methods in Insurance (Wüthrich & Merz, 2008), Chapter 2: Basic Methods. The repository contains R implementations of two core reserving techniques:

1. Chain-Ladder Method (Distribution-Free)

1.1. Weighted version - Standard volume-weighted development factors (Eq. 2.4). Reference: Chapter 2.1 (Mack's distribution-free model) Development factors are estimated using a volume-weighted average of individual ratios. This approach minimizes estimator variance and is the standard in Chain-Ladder applications.

1.2. Simple average version - A simple (unweighted) average of the ratios can be used. Useful for simplicity or robustness against outliers.

2. Bornhuetter-Ferguson Method - Combines prior ultimate estimates with Chain-Ladder development patterns. Reference: Chapter 2.2 (Model Assumptions 2.8-2.9)

Note: The numerical results in this implementation may differ slightly from those in Wüthrich & Merz (2008), as the book uses rounded values in intermediate steps. This R code uses full numeric precision. However, the starting triangle (Chapter 2, Table 2.2) is exactly the same, ensuring methodological consistency.