Bias and Fairness

⏱️ 12 min πŸ“š Lesson 8 of 11
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Welcome Back!

Once we learned how to evaluate models, it’s crucial to recognize that a high-performing model can still be unfair. This lesson explores bias and fairness, showing how models can inherit biases from data and how we can work to ensure equitable outcomes across different groups.

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What is Bias?

In ML, bias means systematic errors that lead to unfair outcomes. It often comes from the data. For example, if a face recognition model is trained mostly on light-skinned faces, it may fail on darker-skinned faces.

This kind of bias means the model works unevenly across different groups, resulting in discriminatory or inaccurate predictions for certain populations.

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Examples of Bias

Real examples include a hiring tool that learned to prefer male candidates because the past data had more men, or a criminal risk model that flagged certain minority groups unfairly due to biased historical data.

These biases happen when the training data reflects historical prejudices or imbalances. The model learns and perpetuates these unfair patterns.

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Fairness

Fairness means the model should treat different groups equitably. Ideally, it should have similar accuracy for different genders, races, etc.

Achieving fairness can be challenging. It requires checking performance across groups and, if needed, adjusting the model or data to treat them equally.

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Reducing Bias

To reduce bias, collect diverse and representative data. For instance, include equal representation of different skin tones in a face dataset.

Sometimes we remove sensitive attributes (like race) from the model, or we re-balance the data. Addressing bias is crucial for creating ethical and trustworthy ML systems.

Quiz: Recognizing Bias

Which Of These Is An Example Of Dataset Bias Affecting A Model?

A
A face ID app making errors on certain skin tones
B
A weather model missing data for one region
C
A recommender system showing only popular items
D
An app that runs slower on older phones

Fill in the Blank

If a model systematically favors one group over another, this indicates an issue of ______.

πŸ’‘ Drag the correct word from below into the blank to complete the sentence.
If a model systematically favors one group over another, this indicates an issue of
.
accuracy
overfitting
variance
bias

Reflection

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Think of a scenario (like an image tagging system). How might biased data lead it to mislabel images of certain people or objects? What steps could you take (data collection or model changes) to make it more fair?

Lesson Completed!

Excellent work! You now understand bias
and fairness in machine learning and how to build more ethical AI systems.