Handling Missing Data

Summary

Deciding whether to drop, fill, or flag missing values — the right choice depends on why the data is missing and how much of it there is, not a single universal rule.

• 1Learn the difference between data missing at random versus missing systematically.
• 2Practice both dropping and imputing (mean/median fill) missing values on the same dataset.
• 3Document which approach you chose and why, for every dataset you clean.