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Investigation 3-7
Weighing the Evidence


After reviewing the five possible explanations for finding an association, students read an article, "Does Playing Video Games Cause Asthma?"  Then students rephrase selected portions of the article so that the evidence discussed is more or less persuasive and begin to identify criteria for determining whether or not an association is causal.  In conclusion, students start to understand how epidemiologists can review the evidence for an association from a variety of studies by using criteria to "weigh the evidence," and make a judgment as to whether or not the association is causal.

Investigation Preparation Checklist

Check alignment with standards.

National or State file

Review Epidemiology Background for Module 3.

Word or PDF file

Review teacher's notes and slides:  [en espaņol:]

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  • PDF: 364KB

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  • Word: 1,778KB

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  • HTML Web file: 1,890KB

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  • PowerPoint file: 706KB

    Copy article, "Playing Video Games Linked to Asthma," for each student and assign to be read prior to the next class.

    Word or PDF file

    Review "Playing Video Games Linked to Asthma" with teacher notes.

    Word or PDF file

    Copy Investigation 3-7: Epi Log Worksheet for each student.  [en espaņol:]

    Word or PDF file

    Estimated Time / Time Management

    Approximately one class period.

    Look For Students To:

    Explain why it is important to distinguish between associations that are causal from those that are not.

    Identify types of evidence that would help identify causal associations.

    Explain how certain types of evidence are more helpful than others in identifying causal associations.

    Explain how causal criteria are used to judge causality.