Precision Metric

What is Precision?

Precision (also called Positive Predictive Value) measures the proportion of positive predictions that were actually correct.

Formula

Precision = TP / (TP + FP)

• TP: True Positives (correctly predicted positive)
• FP: False Positives (incorrectly predicted positive)

Interpretation

• High Precision: Few false alarms
• Low Precision: Many false positives

When Precision Matters

• When false positives are costly (e.g., unnecessary treatments)
• Spam detection (don't want to miss real emails)
• Quality control (don't want to discard good products)

Related Terms

• Recall: Ability to find all positives
• F1 Score: Balances precision and recall