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# False Flags

## How accurate should government surveillance be?

How accurate should government surveillance be? In 2013, it was revealed that the U.S. government was secretly monitoring its citizens’ phone calls and internet traffic through a program called PRISM. The goal was to identify potential threats and catch would-be terrorists.

In this lesson, students calculate conditional probabilities to determine the likelihood of false-positives and false-negatives, and discuss the tradeoffs between safety and accuracy.

### REAL WORLD TAKEAWAYS

• United States National Security Agency (NSA) conducts a global surveillance program called PRISM in which they collect online communications, including from Americans who weren’t/aren’t aware.
• At some points in time, this government surveillance has been controversial: It’s intended to flag dangerous individuals and monitor their communications to keep America safe, but it may also flag innocent individuals.

### MATH OBJECTIVES

• Model related probabilistic events using Venn diagrams
• Apply Bayes Theorem given conditional probabilities
• Use probabilities to predict the consequences of a real-world policy

Appropriate most times as students are developing conceptual understanding.
Algebra 2