Detectives in the Classroom – Investigation 3
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Reversed Time Order Is the association causal? Detectives in the Classroom – Investigation 3-5: Reversed Time Order Where are we and where are we going? 1 How is this disease distributed? 2 Is there an association? Hypotheses What’s my hypothesis? 3 Is the association causal? Did the exposure and the disease turn up together? Why did the exposure and the disease turn up together? 4 What should be done to prevent the disease? 5 Did the prevention strategy work? Detectives in the Classroom – Investigation 3-5: Reversed Time Order Investigation 3-5 1. Cause 2. Chance 3. Confounding 4. Reversed Time Order 5. Detectives in the Classroom – Investigation 3-5: Reversed Time Order Which came first? Egg Chicken Detectives in the Classroom – Investigation 3-5: Reversed Time Order Scenario 1 Detectives in the Classroom – Investigation 3-5: Reversed Time Order Scenario 2 Detectives in the Classroom – Investigation 3-5: Reversed Time Order Scenario 3 Detectives in the Classroom – Investigation 3-5: Reversed Time Order Which came first? Egg Chicken Detectives in the Classroom – Investigation 3-5: Reversed Time Order Epi Talk Reversed Time Order When the hypothesized time order of an exposure and an outcome is actually reversed and the outcome really comes before the exposure. Detectives in the Classroom – Investigation 3-5: Reversed Time Order Flow Diagram DZ E DZ Random Assignment Healthy People DZ E - DZ Time Detectives in the Classroom – Investigation 3-5: Reversed Time Order Flow Diagram DZ E DZ Healthy People DZ E - DZ Time Detectives in the Classroom – Investigation 3-5: Reversed Time Order Flow Diagram E DZ E - E DZ E Time Detectives in the Classroom – Investigation 3-5: Reversed Time Order Flow Diagram E - E DZ DZ Time Detectives in the Classroom – Investigation 3-5: Reversed Time Order Which came first? Exposure or Outcome? Study Design: Trial Study Design: Cohort Study DZ DZ E E DZ Random Assignment Healthy People DZ Healthy People DZ DZ E E - DZ ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ - DZ ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Time Time Study Design: Case-Control Study Study Design: Cross-Sectional Study E E - DZ E E - E DZ DZ E DZ ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Time ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Time Detectives in the Classroom – Investigation 3-5: Reversed Time Order Epi Log Worksheet Detectives in the Classroom – Investigation 3-5: Reversed Time Order 1 Which came first? Exposure or Outcome? 1 1st 2nd Study Design: Trial Study Design: Cohort Study DZ DZ E E DZ DZ Random Assignment Healthy People Healthy People DZ DZ E E - - DZ ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ DZ ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Time 3rd Time Study Design: Case-Control Study 4th Study Design: Cross-Sectional Study E E - DZ E E - E DZ DZ E DZ ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Time ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Time Detectives in the Classroom – Investigation 3-5: Reversed Time Order Which came first? Exposure Outcome Detectives in the Classroom – Investigation 3-5: Reversed Time Order Scenario 4 Watching TV No Watching TV Overweight No Overweight Watching TV Overweight Detectives in the Classroom – Investigation 3-5: Reversed Time Order Count, Divide, and Compare (CDC) Is there an association? Count TV Overweight No Overweight Total 23 9 32 a b 7 23 32 or Relative Risk 71.8% = c d No TV Risks 15 22 7 22 or 2.3 31.8% Compare Divide Did watching TV and being overweight turn up together? Detectives in the Classroom – Investigation 3-5: Reversed Time Order Time Order Watching TV No Watching TV Overweight No Overweight Watching TV Overweight Detectives in the Classroom – Investigation 3-5: Reversed Time Order Time Order Watching TV No Watching TV Overweight No Overweight X Watching TV Overweight Detectives in the Classroom – Investigation 3-5: Reversed Time Order Time Order Watching TV No Watching TV Overweight No Overweight X Watching TV Overweight Detectives in the Classroom – Investigation 3-5: Reversed Time Order Which came first? Watching TV Overweight Detectives in the Classroom – Investigation 3-5: Reversed Time Order Watching TV Scenario causes 5weight gain. Cigarette Watching TV Smoking No No Cigarette Watching TV Smoking Overweight Depression No Overweight Depression Cigarette Watching TV Smoking Depression Overweight Detectives in the Classroom – Investigation 3-5: Reversed Time Order Count, Divide, and Compare (CDC) Is there an association? Count Cigarette Smoking Depression No Depression Total 38 83 121 a b No Cigarette Smoking c d 59 196 255 Risks 38 121 59 255 or Relative Risk 31.4% = or 1.4 23.1% Compare Divide Did cigarette smoking and depression turn up together? Detectives in the Classroom – Investigation 3-5: Reversed Time Order Watching TV Time causes Order weight gain. Cigarette Watching TV Smoking No No Cigarette Watching TV Smoking Overweight Depression No Overweight Depression Cigarette Watching TV Smoking Depression Overweight Detectives in the Classroom – Investigation 3-5: Reversed Time Order Time Order Cigarette Watching TV Smoking No No Cigarette Watching TV Smoking Overweight Depression No Overweight Depression X Cigarette Watching TV Smoking Depression Overweight Detectives in the Classroom – Investigation 3-5: Reversed Time Order Time Order Cigarette Watching TV Smoking No No Cigarette Watching TV Smoking Overweight Depression No Overweight Depression X Cigarette Watching TV Smoking Depression Overweight Detectives in the Classroom – Investigation 3-5: Reversed Time Order Which came first? Cigarette Smoking Depression Detectives in the Classroom – Investigation 3-5: Reversed Time Order Scenario 6 Detectives in the Classroom – Investigation 3-5: Reversed Time Order Violent Video Games Detectives in the Classroom – Investigation 3-5: Reversed Time Order Violent Video Games Detectives in the Classroom – Investigation 3-5: Reversed Time Order Violent Video Games Detectives in the Classroom – Investigation 3-5: Reversed Time Order Violent Video Games Detectives in the Classroom – Investigation 3-5: Reversed Time Order Violent Video Games Detectives in the Classroom – Investigation 3-5: Reversed Time Order Violent Video Games Can Increase Aggression Violent Video Games No Violent Video Games Aggression No Aggression Violent Video Games Aggression Detectives in the Classroom – Investigation 3-5: Reversed Time Order Violent Video Games Can Increase Aggression Violent Video Games No Violent Video Games Aggression x Violent Video Games No Aggression Aggression Detectives in the Classroom – Investigation 3-5: Reversed Time Order Violent Video Games Can Increase Aggression Violent Video Games No Violent Video Games Aggression x Violent Video Games No Aggression Aggression Detectives in the Classroom – Investigation 3-5: Reversed Time Order Which came first? Violent Video Games Aggression Detectives in the Classroom – Investigation 3-5: Reversed Time Order In the News Municipalities Can Limit Access to Violent Video Games 4 / 29 / 2002 A federal judge ruled that local governments should have the authority to limit children's access to violent video games, the Associated Press reported April 24. The ruling was made in a case brought by a video-game industry group against a St. Louis (Mo.) County ordinance. The ordinance, passed in 2000, regulates access to arcade and home video games. It requires children under 17 to have parental consent before they can purchase or play violent or sexually explicit games. Implementation of the ordinance was suspended until July 1 after the Interactive Digital Software Association sued the county. In making his ruling, Senior U.S. District Judge Stephen Limbaugh determined that the video games are not constitutionally protected forms of speech. Detectives in the Classroom – Investigation 3-5: Reversed Time Order Which came first? Exposure No Exposure Outcome No Outcome Exposure ? Outcome Detectives in the Classroom – Investigation 3-5: Reversed Time Order Epi Log Worksheet Detectives in the Classroom – Investigation 3-5: Reversed Time Order 2 Reversed Time Order It is possible that watch TV people who __________ be overweight are more likely to ____________. But it is also possible that overweight people who are __________ watch TV are more likely to __________. Detectives in the Classroom – Investigation 3-5: Reversed Time Order 2 Epi Teams Detectives in the Classroom – Investigation 3-5: Reversed Time Order Time Order Detectives in the Classroom – Investigation 3-5: Reversed Time Order Epi Log Worksheet 3-6 Detectives in the Classroom – Investigation 3-5: Reversed Time Order Time Order Detectives in the Classroom – Investigation 3-5: Reversed Time Order Explanations for Finding an Association Could the association have been found because of reversed time order? Detectives in the Classroom – Investigation 3-5: Reversed Time Order Which came first? Exposure or Outcome? Study Design: Trial Study Design: Cohort Study DZ DZ E E DZ Random Assignment Healthy People DZ Healthy People DZ DZ E E - DZ ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ - DZ ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Time Time Study Design: Case-Control Study Study Design: Cross-Sectional Study E E - DZ E E - E DZ DZ E DZ ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Time ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Time Detectives in the Classroom – Investigation 3-5: Reversed Time Order Explanations for Finding an Association 1. Cause 2. Chance 3. Confounding 4. Reversed Time Order 5. Study Links Eating M&M’s To Decreased Risk of Flu Detectives in the Classroom – Investigation 3-5: Reversed Time Order Reversed Time Order Investigation 3-5 has ended. Detectives in the Classroom – Investigation 3-5: Reversed Time Order
