ESTs, evidence-based practice, and practice-based evidence
Three terms that are routinely confused, and the arguments each one is used to win.
Empirically supported treatments
A specific protocol shown to work for a specific disorder in randomised trials meeting defined criteria. The Chambless criteria — two independent well-designed trials showing superiority to placebo or another treatment, or equivalence to an established treatment, with treatment manuals and specified populations — set the standard in the 1990s and generated the lists that followed.
The case for lists
- Patients are entitled to treatments known to work
- Without criteria, anything can be sold as therapy
- Manualisation makes training and dissemination possible
- Lists put pressure on the field to generate evidence
The case against
- Privileges what is easy to manualise and to trial
- Trial populations are unlike clinic populations
- Ignores therapist effects, which are larger than treatment effects
- Confuses absence of evidence with evidence of absence
Evidence-based practice
A decision process rather than a list, and the distinction matters enormously in argument. The APA definition has three components: best available research evidence, clinical expertise, and patient characteristics, culture, values and preferences. Citing "evidence-based practice" to mean "use a treatment from the list" collapses three legs into one.
Practice-based evidence
Data generated by routine clinical work rather than by trials. Practice research networks, routine outcome monitoring and large service datasets address the external validity problem that trials cannot: real patients, real comorbidity, real clinicians, real conditions. The trade-off is the absence of randomisation and therefore of causal inference.
The two are complementary rather than competing. Trials establish that a treatment can work; practice-based evidence establishes whether it does work, here, delivered by these clinicians to these patients.
Sources
APA Presidential Task Force on Evidence-Based Practice (2006). Evidence-based practice in psychology. American Psychologist, 61(4), 271–285
guidelineChambless, D. L., & Hollon, S. D. (1998). Defining empirically supported therapies. Journal of Consulting and Clinical Psychology, 66(1), 7–18
articleCastonguay, L. G., Nordberg, S. S., Schut, A. J., & Constantino, M. J. (2010). Psychotherapy research. In The Corsini Encyclopedia of Psychology (4th ed.)
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