How important are the common factors in psychotherapy? An update
Also known as How important are the common factors in psychotherapy?
Bruce Wampold's 2015 review of the evidence that common factors drive therapy's benefits
At a glance
What it found
Common factors matter, Specific ingredients add little, Therapists matter
See all 3Key ideas
The initial bond, Pathway 1: the real relationship, Pathway 2: expectations …
See all 4The numbers
Alliance, Empathy, regard, genuineness, Expectations …
See all 5Examples from the paper
Many mechanisms
Criticism and limits
The common factors debate
Read next
The Great Psychotherapy Debate, The alliance in adult psychotherapy: a meta-analytic synthesis, The Efficacy of Cognitive Behavioral Therapy: A Review of Meta-analyses
See all 3Connections
Bruce Wampold, Common factors theory and 3 others
See all 5
Also on this page: Key facts · Links · Sources · Related pages
- The paper sets out the contextual model of psychotherapy and tests it against meta-analyses.
- Therapy works through a real relationship, through expectations, and through specific ingredients that prompt healthy actions.
- Alliance, empathy, expectations, cultural adaptation and therapist differences each relate to outcome.
- Evidence for specific ingredients, adherence and competence is weak.
- It concludes that the common factors are important for producing the benefits of psychotherapy.
Why it matters
- The shortest way into the common factors argument: ten pages, open to read, with every key effect size in one place.
Key facts
- Author
- Bruce E. Wampold (University of Wisconsin–Madison; Modum Bad Psychiatric Center, Norway)1
- Published
- October 20151
- Journal
- World Psychiatry, vol. 14, issue 3, pp. 270–2771
- DOI
- 10.1002/wps.202381
- PMCID
- PMC45926391
- Design
- Narrative review, mainly of meta-analyses1
- Main result
- Alliance and outcome: about .27, equivalent to Cohen's d = 0.57; empathy d = 0.63; expectations d = 0.242
- Specific factors
- Treatment differences at most about d = 0.20; dismantling studies d = 0.01; adherence d = 0.04; competence d = 0.142
- Cited by
- 715 (Europe PMC count, October 2026)1
What it found
-
Common factors matter1
The evidence supports the conclusion that the common factors are important for producing the benefits of psychotherapy.
-
Specific ingredients add little2
Removing an ingredient from a treatment barely changes outcomes (d = 0.01); adding one helps a little (d = 0.28).
-
Therapists matter2
Therapist effects are modest in clinical trials (d = 0.35) and relatively large in naturalistic settings (d = 0.55).
Key ideas
-
The initial bond2
A therapeutic bond has to form before any pathway works; a strong alliance is needed for the other two.
-
Pathway 1: the real relationship2
A genuine human connection with an empathic therapist can itself promote health, especially for people with little social support.
-
Pathway 2: expectations2
A believable explanation of the distress builds the belief that the treatment's tasks will help.
-
Pathway 3: specific ingredients2
Each treatment's techniques prompt healthy actions, whatever the theory behind them.
The numbers
-
Alliance2
About .27 correlation with outcome, equivalent to d = 0.57; goal consensus and collaboration d = 0.72.
-
Empathy, regard, genuineness2
Empathy d = 0.63; positive regard d = 0.56; congruence d = 0.49.
-
Expectations2
Small but significant: d = 0.24 across 46 studies.
-
Cultural adaptation2
Modest: d = 0.32 across 21 studies.
-
Adherence and competence2
Following the manual (d = 0.04) or rated competence (d = 0.14) barely predicts outcome.
Examples from the paper
-
Many mechanisms2
"psychotherapy does not have a unitary influence on patients, but rather works through various mechanisms."
Criticism and limits
-
The common factors debate3
Critics argue common factors theory dismisses specific techniques, reduces to a good relationship, or is not scientific; supporters dispute this.
Read next
-
The Great Psychotherapy Debate
The book-length version of the argument.
-
The alliance in adult psychotherapy: a meta-analytic synthesis
The 2018 meta-analysis behind the alliance figure.
-
The Efficacy of Cognitive Behavioral Therapy: A Review of Meta-analyses
The case for one specific treatment's evidence base.
Connections
Links
Sources
- Wampold BE. How important are the common factors in psychotherapy? An update. World Psychiatry 2015;14(3):270-277 (Europe PMC) (opens europepmc.org)
- How important are the common factors in psychotherapy? An update (full text, PMC) (opens pmc.ncbi.nlm.nih.gov)
- Common factors theory (Wikipedia) (opens en.wikipedia.org)
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