2x2 Contingency Table Analysis

Enter patient counts to compute OR, RR, ARR, NNT, and Chi-Square statistics.

Outcome +
Outcome -
Intervention
Control

Comprehensive Guide: 2x2 Contingency Table Analysis

The Clinical Importance

The 2x2 contingency table is the cornerstone of epidemiological studies, used to evaluate the association between an exposure/intervention and an outcome. It is vital for calculating Odds Ratios (OR) in case-control studies and Relative Risks (RR) in cohort studies.

The Statistical Science

The engine computes exact OR, RR, Absolute Risk Reduction (ARR), and Number Needed to Treat (NNT). Crucially, if any expected cell count falls below 5, the engine automatically applies Yates's Continuity Correction to the Chi-Square calculation to prevent Type I errors, ensuring robust p-values.

Step-by-Step Instructions

  1. Step 1: Enter patient counts for Intervention/Exposure and Control groups into the grid.
  2. Step 2: Review the generated statistics.
  3. Step 3: Use the provided metrics (including 95% Confidence Intervals) directly in your results section.