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The What Works Clearinghouse has released the What Works Clearinghouse Standards Handbook, Version 4.1 and the What Works Clearinghouse Procedures Handbook, Version 4.1. The approaches that researchers use to measure and communicate the impacts of interventions are constantly evolving. The What Works Clearinghouse team has designed the updated standards and procedures handbooks to keep pace with the evolving nature of education research and to provide additional clarity for WWC reviewers and users.

The updates include the following substantive changes among other revisions:

  • Procedures for estimating an effect size when multiple effects are present in a single domain in a single study.
  • Procedures for synthesizing intervention effects in intervention reports using fixed-effects meta-analysis.
  • Procedures for determining effectiveness ratings in intervention reports.
  • Procedures for calculating effect sizes from single case design studies.
  • Several additional changes to procedures for effect size estimation, search guidance, and clarification of existing standards and procedures.

Learn more about these changes in a webinar:

January 22, 2020
2:00–3:30 p.m. Eastern Time

Register here


  • Joseph Taylor, University of Colorado, Colorado Springs and American Institutes for Research
  • Jeffrey Valentine, University of Louisville


  • Sarah Caverly, American Institutes for Research

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