Welcome to Parsimony’s blog, where we help K-12 educators identify evidence based ways to maximize student outcomes.

This blog post is part of our What Works Clearinghouse review series. The What Works Clearinghouse (WWC) is an initiative by the Institute of Education Sciences (IES) which is the independent statistics, research, and evaluation arm of the United States Department of Education. WWC estimates the effectiveness of programs by evaluating the quality and quantity of evidence for that program.

This week’s blog post is about the evidence behind The Incredible Years’s impact on students. Here’s the short version:

The Incredible Years is designed for children (ages 0–12) with challenging behaviors and focuses on building social and emotional skills. Lessons can be delivered to children referred for difficult behavior or to an entire classroom as a preventative measure. The program consists of 20- to 30-minute lessons 2–3 times a week.

The evidence for The Incredible Years covers students in pre-kindergarten through 2nd grade.

The outcomes examined include: external behavior and social outcomes. Here’s what the evidence suggests about The Incredible Years’s impact on each outcome:

  • External behavior: Positive impact (an average student would be expected to improve by 20 percentile points)
  • Social outcomes: Positive impact (an average student would be expected to improve by 18 percentile points)

The studies looking into The Incredible Years had student samples that were in urban areas in Washington, had students who were White, and were male and female.

You can find the full report from the What Works Clearinghouse here:


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