EPPP Practice Test 2026 – Your All-in-One Resource for Psychology Exam Success!

The mean effect size identified by Smith, Glass, and Miller in their comprehensive meta-analysis of psychotherapy outcomes is indeed .85. This value is significant as it reflects a substantial positive impact of psychotherapy on the clients' mental health and well-being.

In the context of this research, an effect size of .85 suggests that psychotherapy tends to lead to outcomes that are better than approximately 81% of individuals who do not receive psychotherapy. This demonstrates the effectiveness of various therapeutic approaches in treating mental health issues, indicating that individuals undergoing therapy generally experience considerable improvement.

Additionally, this effect size underscores the importance of evidence-based practice in psychology, as it provides a quantifiable measure of therapy's success, reinforcing the value of engaging in therapeutic interventions for those in need.