81 EUROPEAN JOURNAL OF BEHAVIOR ANALYSIS NUMBER 1 (SUMMER 2008) 2008, 9, 81 - 95 81 Over the past 30 years, behavioral scien- tists have identiied numerous evidence-based treatment and prevention programs, policies, and other practices (e.g., Biglan et al., 2004). Societies have the potential to help achieve a signiicant reduction in the prevalence of the most common and costly behavioral and psychological problems that develop in child- hood and adolescence—if they can implement evidence-based practices widely and efectively. Putting it more positively, we could assure that many more young people reach adulthood with the skills and interests needed to become productive and caring adults who contribute to the wellbeing of others. However, there is no guarantee that existing knowledge will result in widespread beneit. We know far more about how to afect young people than we know about how to inluence the social systems that will have to adopt evidence-based practices if the fruits of recent discoveries are going to be realized. Case studies have a venerable history in the development of efective treatments. One of the seminal events in the development of behavior therapy was Joseph Wolpe’s treatment of a series of phobic clients with systematic desensitiza- tion. Careful documentation of efects with individual cases lays the groundwork for more systematic experimental evaluation (e.g., Paul, 1967). Case studies are especially valuable when the units under study are not individuals, but treatment agencies or even whole countries and research is therefore very expensive. The Evidence-based Practices Movement A Growing Body of Eicacious and Efective Interventions The evidence-based practice movement consists of a variety of eforts to bring into widespread use, programs, policies, and other practices already shown by experimental evalu- ation to afect psychological or behavioral func- tioning. Beginning in the 1960s, psychologists and educational researchers began to report treatment procedures that were demonstrably more efective than the procedures with which they were compared. Gordon Paul conducted the irst randomized trial of Wolpe’s system- atic desensitization. Wesley Becker (Becker, Madsen, & Arnold, 1967; Madsen, Becker, & homas, 1968) showed in a time-series design that teachers' use of rules, praise, and ignoring led to signiicantly better classroom coopera- tion. In the ensuing years, researchers reported on interventions that were beneicial for virtu- The Evolution of Evidence-based Practices Anthony Biglan Center on Early Adolescence, Oregon Research Institute Terje Ogden Norwegian Center of Child Behavioral Development, University of Oslo his paper addresses one facet of the efort to translate growing behavioral science knowledge into concrete beneits - the evidence-based practices movement. We describe recent developments in this ef- fort and present as a case study the experience of Norway in implementing evidence-based practices. Key words: Evidence-based, empirically supported, dissemination Corresponding author is: Anthony Biglan, Ph.D., Senior Scientist, Oregon Research Institute, 1715 Franklin Boulevard, Eugene, Oregon 97403-2183 USA. Email: tony@ori.org Acknowledgements: The National Cancer Institute (CA38273) and the National Institute on Drug Abuse (DA018760) provided inancial support for the completion of the work on this manuscript.