Bias Assessment

Tutorial 2 of 4

1. Introduction

This tutorial aims to guide you through the process of detecting and mitigating bias in AI systems. Bias in AI is a significant issue that can skew outcomes, often in ways that disadvantage certain groups. This tutorial will help you understand how to identify and deal with bias in AI.

By the end of this tutorial, you will learn about:

  • Different types of bias in AI
  • How to detect bias in your AI models
  • Techniques to mitigate bias

Prerequisites: A basic understanding of AI and machine learning is beneficial.

2. Step-by-Step Guide

a. Understanding Bias in AI

Bias in AI can occur due to various reasons like skewed data, prejudice in data collection, etc. It can lead to unfair outcomes, which can be harmful.

b. Detecting Bias in AI

Detecting bias involves evaluating your model's performance across different groups. For example, if your AI model is for credit approval, check if the approval rates differ across gender, age, or ethnicity.

c. Mitigating Bias in AI

Mitigating bias is a complex task that involves several steps like collecting diverse data, being transparent about your AI's limitations, and regularly reviewing and updating your AI models.

3. Code Examples

a. Detecting Bias

# Import necessary libraries
from sklearn.metrics import accuracy_score

# Let's assume y_test are the true labels and y_pred are the predicted labels
y_test = [...]
y_pred = [...]

# Calculate accuracy
total_accuracy = accuracy_score(y_test, y_pred)

# Calculate accuracy for a subgroup, e.g., females
female_accuracy = accuracy_score(y_test[female_indices], y_pred[female_indices])

# If there is a significant difference between total_accuracy and female_accuracy, there might be a bias

b. Mitigating Bias

# Let's assume we have a dataset with gender bias. We can mitigate it by upsampling the minority class

# Import necessary libraries
from sklearn.utils import resample

# Separate majority and minority classes
df_majority = df[df.gender=="male"]
df_minority = df[df.gender=="female"]

# Upsample minority class
df_minority_upsampled = resample(df_minority, 
                                 replace=True,     # sample with replacement
                                 n_samples=df_majority.shape[0],    # to match majority class
                                 random_state=123) # reproducible results

# Combine majority class with upsampled minority class
df_upsampled = pd.concat([df_majority, df_minority_upsampled])

# Now the data has less gender bias

4. Summary

In this tutorial, we covered different types of bias in AI, how to detect them, and techniques to mitigate them. Keep in mind that completely eliminating bias is impossible, but we can reduce it to a certain extent.

5. Practice Exercises

  1. Exercise: Use the accuracy_score method from sklearn.metrics to calculate the accuracy of your model for different subgroups in your data.

Solution: The solution is similar to the code snippet in the 'Detecting Bias' section. Replace 'female_indices' with indices for the subgroup you want to calculate the accuracy for.

  1. Exercise: Use the resample method from sklearn.utils to upsample a minority class in your data and mitigate bias.

Solution: The solution is similar to the code snippet in the 'Mitigating Bias' section. Replace 'df_minority' and 'df_majority' with your minority and majority classes.

Remember, the key to dealing with bias is staying aware, constantly evaluating your models, and taking steps to mitigate bias when you find it. Happy learning!