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On April 18, 2019, the What Works Clearinghouse (WWC) hosted a webinar on confounding in group design studies.

The webinar covered the following:

  • An overview of the WWC definition of confounds and why they are problematic
  • An in-depth discussion of confounds and practice identifying them
  • An examination of the prevalence of confounding in WWC-reviewed studies

Participants learned strategies and tips for identifying confounds when reviewing studies for the WWC.

This webinar was intended for researchers, WWC reviewers, and practitioners who want to learn more about confounding in group design studies, including why confounds are problematic and how to identify them.


  • Herbert Turner, Principal Scientist, ANALYTICA
  • Natalya Gnedko-Berry, Senior Researcher, American Institutes for Research

Released: April 2019

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