Power to detect homework effects in psychotherapy outcome research

Nikolaos Kazantzis

Research output: Contribution to journalArticleResearchpeer-review

51 Citations (Scopus)


Studies of homework effects in psychotherapy outcome have produced inconsistent results. Although these findings may reflect the comparability of psychotherapy with and without homework assignments, many of these studies may not have been sensitive enough to detect the effects sizes (ESs) likely to be found when examining homework effects; The present study evaluated the power of homework research and showed that, on average, current power levels are relatively weak in controlled studies ranging from 0.58 for large ESs to 0.09 for small ESs. Thus, inconsistent findings between studies may very well be due to low statistical power.

Original languageEnglish
Pages (from-to)166-170
Number of pages5
JournalJournal of Consulting and Clinical Psychology
Issue number1
Publication statusPublished - 1 Jan 2000
Externally publishedYes

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