Psychotherapy Blog

 

The Lake Wobegon Effect

Posted by Tony Rousmaniere, PsyD on 3/10/11 - 5:49 PM
How good a therapist are you?

Odds are, you think you’re pretty good. A recent study[i] of 129 therapists found that over 90% self-rated their psychotherapy skills at the 75th percentile or greater.  All of the therapists rated themselves above the 50th percentile.

In his fascinating new book on therapy outcome, Michael Lambert calls this positive self-assessment bias the “Lake Wobegon effect”. While it is true that the overall industry-wide effectiveness rates for psychotherapy are very good, our blindness to our weaknesses is dangerous.
 
Lambert points out that 30% to 50% of our clients don’t improve in treatment. Even more alarming, roughly 8% of clients get worse in treatment.  (Deterioration rates of children and adolescents may be as high as 12% to 24%.)
 
If all of us are above average, then who is causing the problems?  

Lambert cites a study in which 20 experienced therapists and 20 therapist trainees were asked to predict the progress of current clients in their caseloads. Of the 550 total clients, the therapists in the study predicted that only three were deteriorating. The actual number of clients who got worse was 40.

Notably, none of the experienced therapists predicted any of the clients in their caseload getting worse, even though they were reminded at the beginning of the study that the industry-wide average deterioration rate is 8%.

How can we fix our blindness towards our weaknesses?  The traditional method of addressing therapist deficits is supervision and consultation, but those only work when we can correctly identify which clients in our caseload are deteriorating.

Lambert proposes using an intriguing actuarial model, in which the clients’ session-by-session data on outcome measures is entered into a computer program. Using a large database of client outcome data, the program is able to alert the therapist when the probability of client deterioration is high. In his book, Lambert cites a few studies that indicate promise with this method.

Understandably, many therapists will be loath to make clinical decisions based on a computer’s calculations. But then how else do we overcome our self-assessment bias and seriously deal with the risk of client deterioration? Whatever tool we choose, this is an important question for our field to address.


[i] Walfish, S., McAlister, B., O’Donnell, P. & Lambert, M. Are all psychotherapists from Lake Wobegon?: An investigation of self-assessment bias in mental health providers. Submitted for publication.
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