ML Pipelines

What Is an ML Pipeline?

A machine learning pipeline is the step-by-step process used to build, test, and deploy a machine learning model. It helps organize the entire workflow from raw data to a working model.

01

Data Collection — Gather examples for the model

02

Data Cleaning — Fix errors and prepare the data

03

Feature Selection — Choose the most useful inputs

04

Training — Teach the model patterns from data

05

Evaluation — Measure model performance

06

Deployment — Make the model available for use

Each step is important. If one step is weak, the final model may perform poorly.

Data Collection

Data collection is the first step in the machine learning pipeline. The model needs examples to learn from, so collecting useful and relevant data is essential.

Examples of Data
  • Customer records
  • Images
  • Text documents
  • Medical records
  • Website activity
  • Financial transactions
  • Sensor data

Why Data Quality Matters

A model can only learn from the data it receives. If the data is poor, incomplete, biased, or inaccurate, the model may learn incorrect patterns.

Good Data
  • Accurate
  • Relevant
  • Complete
  • Representative
  • Properly labeled
Poor Data
  • Missing values
  • Incorrect labels
  • Biased examples
  • Duplicate records

Data Cleaning

Raw data is often messy. Data cleaning prepares the dataset by fixing problems before training begins.

Common Data Problems
  • Missing values
  • Duplicate rows
  • Incorrect labels
  • Inconsistent formats
  • Outliers
  • Invalid values

Examples of Data Cleaning

Cleaning Actions
  • Remove duplicate records
  • Fill missing values
  • Fix spelling errors
  • Convert text to lowercase
  • Remove invalid entries
  • Standardize date formats

Feature Selection

Features are the input variables used by the model. Feature selection means choosing the most useful features and removing features that do not help.

House Price Prediction

Useful Features

  • Square footage
  • Location
  • Number of bedrooms
  • Age of house

Less Useful Feature — Random ID number

Why Feature Selection Matters

Benefits of Feature Selection
  • Faster training
  • Better accuracy
  • Less overfitting
  • Simpler models
  • Easier interpretation

Training

Training is the stage where the model learns patterns from data. The model studies examples and adjusts itself to make better predictions.

01

Model receives input data

02

Model makes a prediction

03

Prediction is compared to the correct answer

04

Error is calculated

05

Model updates itself

06

Process repeats until model improves

Evaluation

Evaluation checks how well the trained model performs on data it has not seen before.

Evaluation Answers
  • Is the model accurate?
  • Does it generalize to new data?
  • Is it overfitting or underfitting?
  • Is it ready for deployment?

Common Evaluation Metrics

Problem TypeCommon Metrics
ClassificationAccuracy, Precision, Recall, F1 Score
RegressionMAE, MSE, RMSE, R-squared

Overfitting and Underfitting in the Pipeline

Signs of Problems

Underfitting — Training and testing accuracy both low

Overfitting — Training very high, testing much lower

Good Fit

Training Accuracy — High

Testing Accuracy — Similar to training accuracy

Deployment

Deployment means making the trained model available for real users, applications, or systems.

Deployment Examples
  • Model integrated into a website
  • API endpoint for predictions
  • Mobile app feature
  • Fraud detection system
  • Recommendation engine
  • Chatbot assistant

Monitoring After Deployment

Machine learning work does not end after deployment. Models should be monitored to make sure they continue working correctly.

Monitoring Checks
  • Accuracy over time
  • Response speed
  • Error rate
  • Bias detection
  • Data drift
  • User feedback

Data Drift

Data drift happens when real-world data changes after a model has been deployed.

Example

A fraud detection model was trained on old fraud patterns.

New fraud tactics appear.

Result — The model becomes less accurate over time.

Monitoring helps detect data drift before the model becomes unreliable.

Retraining the Model

If a model becomes outdated, it may need to be retrained using newer data.

01

Collect new data

02

Clean and prepare the data

03

Update features if needed

04

Train the model again

05

Evaluate and redeploy the updated model

ML Pipeline Summary

Pipeline StepPurpose
Data CollectionGather examples for the model
Data CleaningFix errors and prepare the data
Feature SelectionChoose useful inputs
TrainingTeach the model patterns
EvaluationMeasure model performance
DeploymentMake the model available for use

Practice Prompt

Imagine you are building a machine learning model that recommends study topics to students.

Describe how you would complete each pipeline step: data collection, data cleaning, feature selection, training, evaluation, and deployment.

Need Help?

Ask the AI if you need help understanding data collection, data cleaning, feature selection, training, evaluation, deployment, or any part of the machine learning pipeline.