Agency Briefing Teacher GuideAgency Briefing Classification: Top Secret / Teacher Resource OPERATION: NUMBERS LIE DURATION: 45 MINUTES Mission Objectives Identify common visual manipulations in charts and graphs (y-axis truncation, scale changes). Distinguish between correlation (events happening together) and causation (one event causing another). Evaluate source credibility by analyzing bias, funding, and data collection methods. Evidence Required Students will complete the "Case Files" worksheet during the investigation. Materials • Truth Sleuths Slide Deck • Case Files Worksheet • Magnifying glasses (optional/prop) Operation Timeline 05m The Hook: The Lie Behind the Numbers Start with a "too good to be true" statistic (e.g., "9 out of 10 dentists recommend sugar for breakfast"). Ask: "Why would someone tell us this?" Introduce the idea that data isn't objective; it's a tool used to persuade. 10m Suspect #1: Misleading Visuals Show graphs with truncated y-axes (starting at 50 instead of 0) or inconsistent intervals. Explain how this exaggerates small differences into massive gaps. Key Question: "Where does the y-axis start? Does the scale change halfway through?" 10m Suspect #2: Correlation vs. Causation Present the "Ice Cream and Drowning" scenario. As ice cream sales rise, so do drownings. Does ice cream cause drowning? No, the third variable is summer heat. Discussion: Brainstorm other "spurious correlations" (e.g., shoe size and reading ability). 10m Suspect #3: Credibility & Bias Discuss how to spot bias. Who paid for the study? Is the sample size too small (e.g., "5 people tried this product")? Is the phrasing biased? 10m Case Closure: Student Investigation Students work on the Case Files Worksheet to apply their detective skills to three real-world (or simulated) data crimes. Support & Extension Scaffolding Provide a "Red Flag Checklist" (e.g., Does it have a title? Is the y-axis zeroed?) to help students focus their analysis. Extension Challenge students to create their own "Misleading Marketing" graph based on a set of honest numbers to see how they can spin the truth.
Truth Sleuths SlidesTop Secret Classified Data Detectives Mission: Spotting the Lie Behind the Numbers Can Numbers Lie? We often think of math as "pure" and "objective." "Numbers don't lie, but people do with numbers." Data is a tool used to persuade. Your job is to find out if you're being told the whole truth. Evidence Log: 001 The Visual Trap Suspect #1 Truncated Axes By starting the Y-axis at 50 instead of 0, a tiny difference looks like a massive lead. Inconsistent Scales Stretching or squishing the axis to change the slope of a line. Check the Y-Axis! Does it start at ZERO? Example: Sales "Boom" 90 100 Starting at 90 makes the 2nd bar look 4x bigger! The False Connection Suspect #2 Ice Cream Sales Go Up Shark Attacks Go Up Does Ice Cream Cause Sharks? No! They are both caused by a Third Variable: SUMMER HEAT Correlation ≠ Causation Follow the Money Suspect #3 "Who is telling the story?" Funding Bias Is a candy company paying for a study on "Why sugar is great"? Sample Size Did they ask 1,000 people or just their 3 best friends? Cherry-Picking Did they only show the data that made them look good? Detective's Rule "Always check the source. If the source has a reason to lie, double-check the data." Your Mission You have been handed three Case Files. Inside each file is a dataset or graph that is highly suspicious. 1 Find the Crime (What's wrong?) 2 Identify the Suspect (Bias, Scaling, or Correlation?) 3 Write your Report (Tell the truth!) Detectives, start your investigation!
Case Files WorksheetFile #402-B Agency Case Files Official Data Investigation Report Detective Name: Badge Number: CASE 01 The Graph Gremlin Suspect: Misleading Visual Evidence: A local newspaper published this graph showing a "massive increase" in city park visitors over two years. 10,500 10,000 2024 2025 "Park Attendance Doubles!" 1. Analyze the Y-Axis. What is the actual numerical difference between 2024 and 2025? 2. Why is the headline "Park Attendance Doubles!" misleading? CASE 02 The Spurious Link Suspect: Correlation vs Causation Evidence: A study found that children who have bigger feet have higher reading scores. The headline reads: "Want to be a better reader? Wear larger shoes!" 1. Foot size and reading scores are correlated (they change together). Does foot size cause reading ability? 2. Identify the "Third Variable" (the hidden factor) that actually explains why both increase. CASE 03 The Biased Witness Suspect: Credibility & Bias Health News Weekly New Study: Soda is more hydrating than water! Researchers at the "Fizzy Drinks Research Lab" (funded by BigPop Corp) found that 4 out of 5 people felt more refreshed after a soda than a plain glass of water. 1. Who funded this study? Why does that matter? 2. What "red flags" do you see in the data or the way it was collected? Return to lead detective upon completion. Official Agency Seal
