63. Confusion Matrix: What Your Model Got Wrong and Why

Your model has 95% accuracy. You ship it. Three weeks later someone tells you it's missing 40% of actual fraud cases. You check. The dataset had 95% legit transactions and 5% fraud. Your model just learned to say "not fraud" every single time. 95% accuracy. Zero fraud caught. That's what happens when you trust accuracy alone. The confusion matrix is the tool that would have caught this immediately. What You'll Learn Here What the four cells of a confusion matrix mean TP, TN, FP, FN with real-wor