August 2003, Vol 93, No. 8 | American Journal of Public Health Glasgow et al. | Peer Reviewed | Public Health Matters | 1261 ��� PUBLIC HEALTH MATTERS ��� The gap between research and practice is well documented. We address one of the underlying reasons for this gap: the assumption that effectiveness research naturally and logically follows from successful efficacy research. These 2 research traditions have evolved different methods and values consequently, there are inherent differ- ences between the characteristics of a successful efficacy intervention versus those of an effectiveness one. Moderating factors that limit robustness across settings, popu- lations, and intervention staff need to be addressed in efficacy studies, as well as in effectiveness trials. Greater attention needs to be paid to documenting intervention reach, adoption, implementation, and maintenance. Recommendations are offered to help close the gap between efficacy and effectiveness research and to guide evaluation and possible adoption of new programs. (Am J Public Health. 2003 93:1261���1267) Why Don���t We See More Translation of Health Promotion Research to Practice? Rethinking the Efficacy-to-Effectiveness Transition | Russell E. Glasgow, PhD, Edward Lichtenstein, PhD, and Alfred C. Marcus, PhD is increasing consensus on evidence-based diabetes management practices to prevent complications and on the importance and cost- effectiveness of these practices.10 However, these recommendations���and especially those related to lifestyle counseling and behavioral issues���are poorly implemented in practice.11���14 This gap between research and practice is the result of several interacting factors, includ- ing limited time and resources of practition- ers, insufficient training,15 lack of feedback and incentives for use of evidence-based practices, and inadequate infrastructure and systems organization to support translation.8,16 In this article, we focus on another reason for the slow and incomplete translation of re- search findings into practice: the logic and as- sumptions behind the design of efficacy and effectiveness research trials. EFFICACY AND EFFECTIVENESS TRIALS Many of the methods used in current pre- vention science are based on 2 influential pa- pers published in the 1980s: Greenwald and Cullen���s17 description of the phases of cancer control research and Flay���s analysis of efficacy and effectiveness research.18 Both papers ar- gued for a logical progression of research de- signs through which promising intervention ideas should proceed. These papers had many positive effects in helping to establish preven- tion research and enhancing acceptability among other disciplines. However, they may also have had an important and inadvertent negative consequence that derives from the assumption that the best candidates for effec- tiveness studies���and later dissemination���are interventions that prove successful in certain types of efficacy research. We argue that this assumption, or at least the way in which it has been operationalized over the past 15 years, has often led to interventions that have low probability of success in real-world settings. To understand this point, it is necessary first to briefly review the seminal papers by Flay18 and Greenwald and Cullen.17 Efficacy trials are defined by Flay as a test of whether a ���pro- gram does more good than harm when deliv- ered under optimum conditions.���18(p451) Effi- cacy trials are characterized by strong control in that a standardized program is delivered in a uniform fashion to a specific, often narrowly defined, homogeneous target audience. Owing to the strict standardization of efficacy trials, any positive (or negative) effect can be directly attributed to the intervention being studied. Effectiveness trials are defined as a test of whether a ���program does more good than harm when delivered under real-world condi- tions.���18(p451) They typically standardize avail- ability and access among a defined popula- tion while allowing implementation and levels of participation to vary on the basis of real- world conditions. The primary goal of an ef- fectiveness trial is to determine whether an intervention works among a broadly defined population. Effectiveness trials that result in no change may be the result of a lack of proper implementation or weak acceptance or adherence by participants.18,19 Greenwald and Cullen17 proposed 5 phases of intervention research presumed to unfold in Despite a growing literature documenting pre- vention and health promotion interventions that have proven successful in well-controlled research, few of these interventions are consis- tently implemented in applied settings. This is true across preventive counseling services for numerous target behaviors, including tobacco use, dietary change, physical activity, and behavioral health issues (e.g., alcohol use, de- pression). Several recent reviews and meta- analyses have documented this gap,1,2 and the task forces on both clinical preventive services and community preventive services have noted that in several areas there is insufficient ap- plied evidence available to make recommenda- tions at present.3���5 Most of the Healthy People 2000 objectives6 were not met, and the even more ambitious goals in Healthy People 2010 are similarly unlikely to be met without signifi- cant changes in the status quo.7,8 To meet these challenges, we will need to have substantially more demonstrations of how to effectively im- plement recommendations in typical settings and in locations serving minority, low-income, and rural populations facing health disparities. This situation is not unique to preventive in- terventions, as strikingly documented in the re- cent Institute of Medicine report Crossing the Chasm,9 which summarizes the similar state of affairs regarding many medical and disease management interventions. For example, there

American Journal of Public Health | August 2003, Vol 93, No. 8 1262 | Public Health Matters | Peer Reviewed | Glasgow et al. ��� PUBLIC HEALTH MATTERS ��� TABLE 1���Distinctive Characteristics of Efficacy and Effectiveness Intervention Studies, Using RE-AIM26,27 Dimensions for Program Evaluation RE-AIM Issue Efficacy Studies Effectiveness Studies Reach Homogeneous, highly motivated sample Broad, heterogeneous, representative sample exclude those with complications, often use a defined population other comorbid problems Efficacy or Intensive, specialized interventions that Brief, feasible interventions not requiring great effectiveness attempt to maximize effect size very expertise adaptable to setting randomized, standardized randomized designs time series, or quasi-experimental designs Adoption Usually 1 setting to reduce variability settings Appeal to and work in multiple settings able with many resources and expert staff to be adapted to fit setting Implementation Implemented by research staff closely Implemented by variety of different staff with following specific protocol competing demands, using adapted protocol Maintenance and Few or no issues focus on individual level. Major issues setting-level maintenance is as cost important as individual-level maintenance a sequential fashion. This continuum begins with Phase I research to formulate and develop intervention hypotheses for future study. Phase II studies develop methodologies that can be used in future efficacy or effectiveness studies. Phase III (efficacy) studies test intervention hy- potheses, using methods that have been tested in Phase II. Thus, Phase III studies are de- signed to test interventions for efficacy, with an emphasis on internal validity, the purpose of which is to establish a causal link between the intervention and outcomes. Given this empha- sis on internal control, Greenwald and Cullen note that Phase III studies can be conducted in settings and with samples that will ���optimize in- terpretation of efficacy,��� including study sam- ples that may be more homogeneous than the ultimate target population, and settings that will maximize management of and control over the research process. The main objective of Phase IV (effective- ness) studies is to measure the impact of an in- tervention when it is tested within a population that is representative of the intended target au- dience. Given that Phase IV studies should yield results that are generalizable, there is also the presumption that the context and setting for delivering the intervention should likewise be generalizable to the intended program users. In Phase V studies, effective Phase IV in- terventions are translated into large-scale dem- onstration projects. The major concern is im- plementation fidelity of an intervention that will now be introduced within even broader populations, including entire communities. This final phase (dissemination research), where col- laboration and coordination with various com- munity partners is likely to receive even greater attention, is intended to provide the necessary data and experience to move inter- ventions into public health service programs at the national, regional, state, and local levels. Greenwald and Cullen specifically advocated that intervention research unfold in a system- atic fashion, building on and extending the body of science accumulated in previous phases. By explicitly defining the difference be- tween Phase III and Phase IV research as being an emphasis on internal control versus repre- sentativeness, both Flay and Greenwald and Cullen assumed that successful Phase III trials would lead naturally to Phase IV trials. Unfor- tunately, this has not occurred.1,11,20 Instead, we currently find ourselves in a situation in which we have many small-scale efficacy studies of unknown generalizability and few successful ef- fectiveness trials.21,22 In particular, we know very little about the representativeness of par- ticipants, settings, or intervention agents partici- pating in health promotion research.1,21 Although the National Cancer Institute no longer emphasizes this linear ���phases of re- search��� model,23,24 the model was extremely influential in guiding an entire generation of research many researchers, reviewers, and editors still use this framework when design- ing, funding, and evaluating research���and in deciding what types of studies are needed to advance a given area. Similar phase models are influential in evaluating prevention effec- tiveness25 and in developing drug therapies. In the remainder of this article, we discuss how this well-intentioned and logical phase of research paradigm may have fallen short of its intended goal, and propose approaches to remedy the present situation. Our primary thesis is that this ���trickle- down��� model of how to translate research into practice���namely, that the optimal way to develop disseminable interventions is to progress from efficacy studies to effectiveness trials to dissemination projects���is inherently flawed, or at least incomplete. We posit that given the respective cultures, values, and methodological traditions that have devel- oped within efficacy versus population-based effectiveness research, it is highly unlikely that interventions that are successful in effi- cacy studies will do well in effectiveness stud- ies, or in real-world applications. Table 1 summarizes the key characteristics of well-designed efficacy and effectiveness tri- als, using the RE-AIM evaluation frame- work.26,27 This model for evaluating interven- tions is intended to refocus priorities on public health issues, and it gives balanced em- phasis to internal and external validity (see http://www.re-aim.org). RE-AIM is an acro- nym for Reach, Efficacy or Effectiveness (de- pending on the stage of research), Adoption, Implementation, and Maintenance. Reach refers to the participation rate among those approached and the representativeness of participants. Factors determining reach are the size and characteristics of the potential au- dience and the barriers to participation (e.g., cost, social and environmental context, neces- sary referrals, transportation, and inconven- ience). Efficacy or effectiveness pertains to the impact of an intervention on specified out- come criteria and includes measures of poten- tial negative outcomes as well as intended re- sults (as recommended by Flay,18 but seldom collected)28,29 (D.A. Dzewaltowski et al., un- published data, 2002). Adoption operates at the setting level and concerns the percentage and representativeness of organizations or set- tings that will conduct a given program. Rogers30 has written extensively on adoption and dissemination issues. Factors associated with adoption include political and cultural fit,