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Investigation 3-4


Students explore the third of five possible explanations for finding an association: confounding.  A confounder is an unobserved exposure that is both associated with an observed exposure and is an actual cause of an outcome.  Given an association between an exposure (viewing R-rated movies) and an outcome (teenage pregnancy) students learn to identify possible confounders and realize the importance of considering confounding when interpreting the results of a study.  Students then identify additional associations and possible confounders.

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: 402KB

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  • PowerPoint file: 919KB

    Copy Investigation 3-4: Epi Log Worksheet for each student.  [en espaņol:]

    Word or PDF file

    Estimated Time / Time Management

    Approximately one class period. Time can be managed by increasing or decreasing the number of 2X2 rate and risk calculations or cell identifications.

    Look For Students To:

    Give several explanations other than cause for finding an association.

    Explain the concept of confounding.

    Explain how an association can be found due to confounding.