Hoddinott et al. BMC Public Health 2010, 10:800 http://www.biomedcentral.com/1471-2458/10/800 We identified this as a gap to which our research could usefully contribute. “Groups” feature in social, political, cultural, educa- tional and work contexts, besides health, and have a variety of meanings, underlying theories and definitions. These are reviewed by Rupert Brown [9], a social psy- chologist, who proposes the following: “A group exists when two or more people define themselves as members of it and when its existence is recognised by at least one other person or group of people who do not so define themselves” The National Institute for Health and Clinical Excel- lence (NICE) behaviour change guidelines distinguish between interventions at the individual, community and population level [10]. Groups are included in the broad category of community interventions, defined as social or family groups linked by networks, geographical loca- tion or another common factor. In this paper, we use a broad definition of health improvement to include health promotion, disease pre- vention (primary and secondary), public health, commu- nity development approaches and social support. We refer to “interventions in group settings” to define what happens to people within the group, the context in which it happens and the relationship between the two. Our definition of the setting refers to an observable health improvement group and the related activities and processes that occur. These include the place where the group meets and we consider the wider aspects of the space occupied by people and things, including the attached meanings and relationships [11]. It also includes the wider geographical, cultural, media, political and organisational environment of health improvement group settings. Our aim is to provide a framework for the design and process evaluation of health improvement interventions in group settings, guided by the literature on designing complex interventions [12]. Detailed discussion of statis- tical aspects are not covered but are important as they need to take account of interactions between both group participants and group leaders [13]. Neither are specific methods of data collection for the process eva- luation of group interventions discussed. Instead our framework poses a series of questions which are impor- tant to consider when designing and evaluating a group intervention. This is central to ecological theories of behaviour, as groups are complex systems with multiple interacting variables, at several levels which require a mixed method approach [14]. We recommend using a toolkit approach [15] to choosing the most appropriate methods (quantitative or qualitative) to answer each question, informed by existing evidence. Page 2 of 9 Development of the framework The framework has developed through our research into breastfeeding support and weight management groups, which included systematic reviews, mixed method group interventions and ethnographic studies [2,16]. Studies included a randomised controlled trial of a policy to provide breastfeeding groups across Scotland [17] with a mixed method evaluation of implementation processes [18]; a controlled intervention study of individual and group peer support for breastfeeding [19,20] and an eth- nographic study of participant and provider experiences of weight management groups [21]. All of these studies conducted in-depth qualitative interviews with partici- pants and providers and group observations. In addition, our studies and this paper were informed by a literature review of health improvement interven- tions for patient groups. We searched Medline, CINAHL, Embase, The Cochrane Library, National Institute for Health and Clinical Excellence (NICE), Psy- cinfo and the International Bibliography of the Social Sciences using group$, class$, club$, workshop$ and program$ as title words for papers published between 1980 until 2009. This was a pragmatic search strategy to limit the number of papers identified and was necessary because of the widespread use of the word “group” in differing contexts in research papers. We identified sys- tematic reviews in relevant areas, for example smoking and alcohol cessation; chronic diseases like diabetes, cancer support and heart disease and searched their reference lists. We also searched our personal reference archives and hand searched references in key papers. We excluded educational groups for teaching students or staff; organisational and management literature on work groups and teams, and treatment groups in mental health, where there is an extensive literature. The framework evolved through an iterative process of mixed method data analysis, reference to the literature, reflection and research team discussion over a period of 6 years. It builds on reviews of group processes [9], small group work in education and work settings [22] and self-help or support groups [23]. What is the evidence for health improvement interventions delivered in group settings? The evidence for health improvement interventions in group settings is varied, reflecting their heterogeneity and complexity and some argue that policy for group interventions to encourage self care has raced ahead of the evidence [24]. Systematic reviews often focus on an individual disease, the type of treatment, or behaviour change theory and they often inappropriately combine the results of interventions delivered individually and in group settings in a meta-analysis [13]. For example, a Cochrane review of additional support for breastfeeding