juniorNaïve Bayes
What is Laplace smoothing in Naïve Bayes?
Updated May 17, 2026
Short answer
Laplace smoothing prevents zero probabilities by adding small constants to counts.
Deep explanation
If a feature never appears in training data for a class, probability becomes zero, breaking Naïve Bayes. Laplace smoothing adds 1 (or α) to all counts to avoid zero probabilities and improve generalization.
Real-world example
Handling unseen words in spam detection systems.
Common mistakes
- Not applying smoothing leading to zero probability collapse.
Follow-up questions
- What is alpha smoothing?
- Why is zero probability dangerous?