AI Glossary Term

What does “Feature Engineering” mean?

Definition

Designing or transforming input variables to make learning easier and more effective.

How Feature Engineering works

Diagram for Feature Engineering, steps in order: Raw data: timestamp 2025-03-14 18:45; then Transform; then Features: weekday=Fri, hour=18, is_weekend=0; then Model learns more easily.Raw data: timestamp 2025-03-14 18:45TransformFeatures: weekday=Fri, hour=18,is_weekend=0Model learns more easily

Example

A taxi-demand model receives raw timestamps. An engineer converts them into hour of day, day of week, and holiday flags, which makes patterns such as rush hour easy for the model to pick up.

Why it matters

On table-based problems, thoughtful features often improve results more than switching algorithms. The work needs domain knowledge.

Common questions

Is feature engineering still needed with deep learning?

Less for images and text, where networks learn features. It remains important for structured business data.

What is a leakage risk here?

Building features using information that would not be available at prediction time, which makes test scores look better than real performance.

How do I know a feature helps?

Compare model performance with and without it on held-out data.

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See also