Unit 5 – Case Studies

Real-world Applications
Public Health

Google Flu Trends Prediction

Google developed an algorithm to predict flu activity by analyzing search queries related to flu symptoms, treatments, and medications. By processing billions of search logs in real-time, the system aimed to provide faster flu forecasts than traditional CDC reporting methods, which typically lagged by one to two weeks.
Key Facts:
  • Analyzed over 50 million U.S. search queries daily
  • Predicted flu activity up to two weeks faster than CDC reports
  • Initially showed 97% accuracy compared to CDC surveillance data
  • Later faced criticism for overestimating flu prevalence during peak seasons
  • Demonstrated both the power and limitations of big data proxy measurements

Focus Question:

Why did Google Flu Trends eventually lose accuracy over time?

Tip: This case highlights the challenge of model drift – when patterns in data shift over time, even large-scale predictive models need continuous retraining and validation against ground truth.
Entertainment

Spotify Music Recommendations

Spotify leverages big data analytics to power its personalized music discovery features like Discover Weekly and Release Radar. By analyzing listening habits, playlist creation, skip rates, and collaborative filtering across 400+ million users, Spotify creates hyper-personalized recommendations that keep users engaged and drive subscription revenue.
Key Facts:
  • Serves over 400 million users across 180+ markets
  • Library contains 100+ million tracks
  • Discover Weekly playlist generated over 2.3 billion streams in its first year
  • Uses NLP to analyze podcast content and lyrics for deeper recommendations
  • Processes over 600 terabytes of data daily for recommendation algorithms

Focus Question:

Which combination of techniques does Spotify use for its recommendation engine?

Tip: Spotify illustrates how Variety V works in practice – combining structured data (play counts), unstructured data (lyrics, audio features), and behavioral data (skip patterns) to create richer insights.
Agriculture

John Deere Precision Agriculture

John Deere transformed traditional farming with precision agriculture technology that collects and analyzes data from sensors on tractors, harvesters, and drones. By combining GPS data, soil composition analysis, weather patterns, and crop health imagery, farmers can optimize planting, irrigation, and harvesting decisions at the individual plant level.
Key Facts:
  • Generates over 500,000 data points per second from field sensors
  • Precision planting can reduce seed waste by up to 75%
  • Variable-rate irrigation reduces water usage by 20-30%
  • Yield maps help farmers increase productivity by 10-15%
  • FarmersOwn data platform processes petabytes of agricultural data

Focus Question:

What makes precision agriculture a big data challenge rather than just simple data collection?

Tip: John Deere demonstrates how big data can revolutionize even the oldest industries – combining all 5 Vs to transform agriculture from intuition-based to data-driven decision making.