This tutorial provides a clear, step-by-step introduction to calculating and interpreting Relative Risk (RR) using R. Designed for biostatistics beginners and epidemiologists, the guide walks through three distinct methodologies: manual extraction from a 2 × 2 table, automated estimation using the epitools package, and adjusted analysis controlling for clinical confounders using log-binomial regression models (glm).

This document provides a clear, step-by-step introduction to calculating and interpreting Odds Ratios (OR) using R. Using a practical health science scenario (Smoking and Lung Cancer), it demonstrates how to build a 2x2 contingency table, extract individual group odds, and replicate the results using both the epitools package and logistic regression (glm).It is specifically designed for beginners, featuring plain-English explanations of data framing, factor levels, and how to avoid common coding layout traps like inverted risk estimates.