The Dodo bird verdict is a controversial topic in clinical psychology which states that all psychotherapies, regardless of their specific components, produce equivalent outcomes. The term originates from Lewis Carroll's novel Alice's Adventures in Wonderland, but the verdict originated from the work of Saul Rosenzweig in the 1930s. The debate surrounding the Dodo bird verdict is important because of its implications for clinical psychology and the psychotherapies made available to clients.
The Dodo bird verdict terminology was coined by Saul Rosenzweig in 1936 to illustrate the notion that all therapies are equally effective. Rosenzweig borrowed the phrase from Lewis Carroll's Alice's Adventures in Wonderland (1865), wherein a number of characters become wet and in order to dry themselves, the Dodo Bird decided to issue a competition: Everyone was to run around the lake until they were dry. Nobody cared to measure how far each person had run, nor how long. When they asked the Dodo who had won, he thought long and hard and then said "Everybody has won and all must have prizes." In the case of psychotherapies, the Dodo bird verdict maintains that all therapies are winners; they all produce equivalent outcomes.[who?]
According to the Dodo bird verdict, all psychotherapies, regardless of their specific components, produce equivalent patient health outcomes. The Dodo bird debate took flight in 1975 when Lester Luborsky, Barton Singer and Lise Luborsky reported the results of one of the first comparative studies demonstrating few significant differences in the outcomes among different psychotherapies. This study spurred a plethora of new studies in both opposition and support of the Dodo bird verdict.
The Dodo bird debate, in brief, is focused on whether or not the specific components of different treatments lead some treatments to outperform other treatments for specific disorders. Supporters of the Dodo bird verdict contend that all psychotherapies are equivalent because of "common factors" that are shared in all treatments (i.e., having a relationship with a therapist who is warm, respectful, and has high expectations for client success). In contrast, critics of the Dodo bird verdict would argue that the specific techniques used in different therapies are important, and all therapies do not produce equivalent outcomes for specific disorders.
The common factors theory states that all therapies in psychology are equally effective because of the common factors they share. The only causal agents in treatment are the common factors and the specific techniques that are unique to treatment strategies are irrelevant.
There is research to support the common factors theory. One common factor is the client-therapist interaction, also known as the therapeutic alliance. A 1992 paper by Lambert showed that nearly 40 percent of the improvement in psychotherapy is from these client-therapist variables. Other researchers have further analyzed the importance of client-therapist variables in treatment. They found that improvement in the patient was due to extra-therapeutic factors, for example patients' thought processes. Data shows that patients with more positive attitudes will have a better chance of experiencing clinical improvement, regardless of the therapist's actions. Furthermore, in a meta-analysis of many studies of psychotherapy, Wampold et al. 2002, found that 7% of the variability in treatment outcome was due to the therapeutic alliance whereas 1% of the variability was due to a specific treatment. The therapists attitude is also a very important causal agent in positive patient change. Najavits and Strupp 1994, demonstrated that a positive, warm, caring, and genuine therapist generated statistically significant differences in patient outcome. Wampold et al. 2002, also found that nearly 70% of the variability in treatment outcome was due to the therapist's attitude toward the efficacy of the treatment. Specific components of therapy are concluded to be relatively frivolous when compared with the more profound and directly patient affecting common factors.
Researchers have studied common factors in detail. Grencavage and Norcross 1990 identified 35 common factors in published sources. The identified common factors were categorized into five main groups: client characteristics, therapist qualities, change processes, treatment structures and relationship elements. Examples of some of the common factors included within these broad categories are persuasion, a healing setting, engagement, the use of rituals and techniques, suggestion, and emotional learning. Recently, Tracey et al. 2003, examined deeper relationships among the categories and common factors. They concluded that there are two dimensions of therapy: feeling and thinking. Within each of the two dimensions are three clusters: bond, information, and role.
Data provide evidence for the Dodo bird verdict. Generally speaking, common factors are responsible for patient improvement instead of any component of a specific treatment. Researchers such as Wampold and Luborsky continue to support this claim in recent articles published in the Behavioral Therapist. Wampold et al. 2010 refutes claims made by Siev et al. 2009 that Wampold 2009 made errors in research. Wampold et al. 2009, suggests that people need to, "accept the importance of the alliance and therapists and remain committed to developing and improving treatments." Wampold continues by saying that techniques could be beneficial in psychotherapy because they are the easiest variables to manipulate. These variables can act to change alliance and other common factors. Common factors can then be closely monitored and carefully distributed to the patient via the therapist.
In opposition to the Dodo bird verdict, there is a growing number of studies demonstrating that some treatments produce better outcomes for particular disorders when compared to other treatments.  Here, in contrast to the common factor theory, specific components of the therapy have shown predictive power. The most compelling evidence against the Dodo bird verdict is illustrated by the research done on anxiety disorders. Many studies have found specific treatment modalities to be beneficial when treating anxiety disorders, specifically cognitive behavioral therapy (CBT). CBT uses techniques from both