Lesson 2 of 10
Data, examples, and useful features
Training data is a collection of examples. Each example has inputs called features; a supervised task also has a target or label the model should learn to predict. For a house-price estimate, inputs might include floor area and location, while the target is the recorded sale price.
Prepare data carefully
- Remove or correct duplicate, invalid, and inconsistent records.
- Decide how to handle missing values and unusual measurements.
- Check that features are available at the moment a real prediction is made.
- Keep personal or sensitive data out unless it is necessary and authorized.
A feature that reveals the answer after the event is data leakage. It can make a model appear excellent in a test and fail in actual use.
Try it: For a delivery-time estimate, list five features available before dispatch and one tempting feature that would cause leakage.