- ML - Home
- ML - Introduction
- ML - Getting Started
- ML - Basic Concepts
- ML - Ecosystem
- ML - Python Libraries
- ML - Applications
- ML - Life Cycle
- ML - Required Skills
- ML - Implementation
- ML - Challenges & Common Issues
- ML - Limitations
- ML - Reallife Examples
- ML - Data Structure
- ML - Mathematics
- ML - Artificial Intelligence
- ML - Neural Networks
- ML - Deep Learning
- ML - Getting Datasets
- ML - Categorical Data
- ML - Data Loading
- ML - Data Understanding
- ML - Data Preparation
- ML - Models
- ML - Supervised Learning
- ML - Unsupervised Learning
- ML - Semi-supervised Learning
- ML - Reinforcement Learning
- ML - Supervised vs. Unsupervised
- Machine Learning Data Visualization
- ML - Data Visualization
- ML - Histograms
- ML - Density Plots
- ML - Box and Whisker Plots
- ML - Correlation Matrix Plots
- ML - Scatter Matrix Plots
- Statistics for Machine Learning
- ML - Statistics
- ML - Mean, Median, Mode
- ML - Standard Deviation
- ML - Percentiles
- ML - Data Distribution
- ML - Skewness and Kurtosis
- ML - Bias and Variance
- ML - Hypothesis
- Regression Analysis In ML
- ML - Regression Analysis
- ML - Linear Regression
- ML - Simple Linear Regression
- ML - Multiple Linear Regression
- ML - Polynomial Regression
- Classification Algorithms In ML
- ML - Classification Algorithms
- ML - Logistic Regression
- ML - K-Nearest Neighbors (KNN)
- ML - Naïve Bayes Algorithm
- ML - Decision Tree Algorithm
- ML - Support Vector Machine
- ML - Random Forest
- ML - Confusion Matrix
- ML - Stochastic Gradient Descent
- Clustering Algorithms In ML
- ML - Clustering Algorithms
- ML - Centroid-Based Clustering
- ML - K-Means Clustering
- ML - K-Medoids Clustering
- ML - Mean-Shift Clustering
- ML - Hierarchical Clustering
- ML - Density-Based Clustering
- ML - DBSCAN Clustering
- ML - OPTICS Clustering
- ML - HDBSCAN Clustering
- ML - BIRCH Clustering
- ML - Affinity Propagation
- ML - Distribution-Based Clustering
- ML - Agglomerative Clustering
- Dimensionality Reduction In ML
- ML - Dimensionality Reduction
- ML - Feature Selection
- ML - Feature Extraction
- ML - Backward Elimination
- ML - Forward Feature Construction
- ML - High Correlation Filter
- ML - Low Variance Filter
- ML - Missing Values Ratio
- ML - Principal Component Analysis
- Reinforcement Learning
- ML - Reinforcement Learning Algorithms
- ML - Exploitation & Exploration
- ML - Q-Learning
- ML - REINFORCE Algorithm
- ML - SARSA Reinforcement Learning
- ML - Actor-critic Method
- ML - Monte Carlo Methods
- ML - Temporal Difference
- Deep Reinforcement Learning
- ML - Deep Reinforcement Learning
- ML - Deep Reinforcement Learning Algorithms
- ML - Deep Q-Networks
- ML - Deep Deterministic Policy Gradient
- ML - Trust Region Methods
- Quantum Machine Learning
- ML - Quantum Machine Learning
- ML - Quantum Machine Learning with Python
- Machine Learning Miscellaneous
- ML - Performance Metrics
- ML - Automatic Workflows
- ML - Boost Model Performance
- ML - Gradient Boosting
- ML - Bootstrap Aggregation (Bagging)
- ML - Cross Validation
- ML - AUC-ROC Curve
- ML - Grid Search
- ML - Data Scaling
- ML - Train and Test
- ML - Association Rules
- ML - Apriori Algorithm
- ML - Gaussian Discriminant Analysis
- ML - Cost Function
- ML - Bayes Theorem
- ML - Precision and Recall
- ML - Adversarial
- ML - Stacking
- ML - Epoch
- ML - Perceptron
- ML - Regularization
- ML - Overfitting
- ML - P-value
- ML - Entropy
- ML - MLOps
- ML - Data Leakage
- ML - Monetizing Machine Learning
- ML - Types of Data
- Machine Learning - Resources
- ML - Quick Guide
- ML - Cheatsheet
- ML - Interview Questions
- ML - Useful Resources
- ML - Discussion
Machine Learning - Data Leakage
Data leakage is a common problem in machine learning that occurs when information from outside the training dataset is used to create or evaluate a model. This can lead to overfitting, where the model is too closely tailored to the training data and performs poorly on new data.
There are two main types of data leakage: Target Leakage and Train-test Contamination
Target Leakage
Target leakage occurs when features that are not available during prediction are used to create the model. For example, if we are predicting whether a customer will churn, and we include the customer's cancellation date as a feature, then the model will have access to information that would not be available in practice. This can lead to unrealistically high accuracy during training and poor performance on new data.
Train-test Contamination
Train-test contamination occurs when information from the test set is inadvertently used in the training process. For example, if we normalize the data based on the mean and standard deviation of the entire dataset instead of just the training set, then the model will have access to information that would not be available in practice. This can lead to overly optimistic estimates of model performance.
How to Prevent Data Leakage?
To prevent data leakage, it is important to carefully preprocess the data and ensure that no information from the test set is used in the training process. Some strategies for preventing data leakage include −
Splitting the data into separate training and test sets before doing any preprocessing or feature engineering.
Only using features that would be available at the time of prediction.
Using cross-validation to evaluate model performance instead of a single train-test split.
Ensuring that all preprocessing steps (such as normalization or scaling) are applied to the training set only and then using the same transformations on the test set.
Being aware of any potential sources of leakage, such as date or time-based features, and handling them appropriately.
Implementation in Python
Here is an example in which we will be using Sklearn breast cancer dataset and ensure that no information from the test set is leaked into the model during training −
Example
from sklearn.datasets import load_breast_cancer
from sklearn.model_selection import train_test_split
from sklearn.pipeline import Pipeline
from sklearn.preprocessing import StandardScaler
from sklearn.svm import SVC
# Load the breast cancer dataset
data = load_breast_cancer()
# Separate features and labels
X, y = data.data, data.target
# Split the data into train and test sets
X_train, X_test, y_train, y_test = train_test_split(X, y, test_size=0.2, random_state=42)
# Define the pipeline
pipeline = Pipeline([
('scaler', StandardScaler()),
('svm', SVC())
])
# Fit the pipeline on the train set
pipeline.fit(X_train, y_train)
# Make predictions on the test set
y_pred = pipeline.predict(X_test)
# Evaluate the model performance
accuracy = accuracy_score(y_test, y_pred)
print("Accuracy:", accuracy)
Output
When you execute this code, it will produce the following output −
Accuracy: 0.9824561403508771