F1 Score
Domain: NLP Fundamentals
🎯 Motivation
The harmonic mean of precision and recall. Balances both into one number for classification tasks.
📋 Concrete Example
Precision 0.8, recall 0.6 -> F1 = 2 * (0.8*0.6)/(0.8+0.6) = 0.68. A single balanced score.
🔗 Analogy
Like a judge who weighs both how many correct answers you got (precision) and how many you missed (recall).