This paper describes the design of the LIKE programme, which aims to tackle the complex problem of childhood overweight and obesity in 10–14-year-old adolescents using a systems dynamics and participatory approach. The LIKE programme focuses on the transition period from 10-years-old to teenager and was implemented in collaboration with the Amsterdam Healthy Weight Programme (AHWP) in Amsterdam-East, the Netherlands. The aim is to develop, implement and evaluate an integrated action programme at the levels of family, school, neighbourhood, health care and city. Following the principles of Participatory Action Research (PAR), we worked with our population and societal stakeholders as co-creators. Applying a system lens, we first obtained a dynamic picture of the pre-existing systems that shape adolescents’ behaviour relating to diet, physical activity, sleep and screen use. The subsequent action programme development was dynamic and adaptive, including quick actions focusing on system elements (quick evaluating, adapting and possibly catalysing further action) and more long-term actions focusing on system goals and/or paradigm change. The programme is supported by a developmental systems evaluation and the Intervention Level Framework, supplemented with routinely collected data on weight status and health behaviour change over a period of five years. In the coming years, we will report how this approach has worked to provide a robust understanding of the programme’s effectiveness within a complex dynamic system. In the meantime, we hope our study design serves as a source of inspiration for other public health intervention studies in complex systems.

Background Systems thinking embraces the complexity of public health problems, including childhood overweight and obesity. It aids in understanding how factors are interrelated, and it can be targeted to produce favourable changes in a system. There is a growing call for systems approaches in public health research, yet limited practical guidance is available on how to evaluate public health programmes within complex adaptive systems. The aim of this paper is to present an evaluation framework that supports researchers in designing systems evaluations in a comprehensive and practical way. Methods We searched the literature for existing public health systems evaluation studies. Key characteristics on how to conduct a systems evaluation were extracted and compared across studies. Next, we overlaid the identified characteristics to the context of the Lifestyle Innovations Based on Youth Knowledge and Experience (LIKE) programme evaluation and analyzed which characteristics were essential to carry out the LIKE evaluation. This resulted in the Evaluation of Programmes in Complex Adaptive Systems (ENCOMPASS) framework. Results The ENCOMPASS framework includes five iterative stages: (1) adopting a system dynamics perspective on the overall evaluation design; (2) defining the system boundaries; (3) understanding the pre-existing system to inform system changes; (4) monitoring dynamic programme output at different system levels; and (5) measuring programme outcome and impact in terms of system changes. Conclusions The value of ENCOMPASS lies in the integration of key characteristics from existing systems evaluation studies, as well as in its practical, applied focus. It can be employed in evaluating public health programmes in complex adaptive systems. Furthermore, ENCOMPASS provides guidance for the entire evaluation process, all the way from understanding the system to developing actions to change it and to measuring system changes. By the nature of systems thinking, the ENCOMPASS framework will likely evolve further over time, as the field expands with more completed studies.

Background: Whole-systems approaches (WSAs) are well placed to tackle the complex local environmental influences on overweight and obesity, yet there are few examples of WSAs in practice. Amsterdam Healthy Weight Approach (AHWA) is a long-term, municipality-led program to improve children's physical activity, diet, and sleep through action in the home, neighborhood, school, and city. Adopting a WSA, local political, physical, social, educational, and healthcare drivers of childhood obesity are viewed as a complex adaptive system. Since 2013, AHWA has reached >15,000 children. During this time, the estimated prevalence of 2-18-year-olds with overweight or obesity in Amsterdam has declined from 21% in 2012 to 18.7% in 2017. Declining trends are rarely observed in cities. There is a need to formally articulate AHWA program theory in order to: (i) inform future program evaluation which can interpret this decline within the context of AHWA and (ii) contribute a real-life example of a WSA to the literature.Methods: This study aimed to formally document the program theory of AHWA to permit future evaluation. A logic framework was developed through extensive document review and discussion, during program implementation. Results:The working principles of the WSA underpinning AHWA were made explicit in an overarching theory of change, articulated in a logic framework. The framework was operationalized using an illustrative example of sugar intake. Conclusions:The logic framework will inform AHWA development, monitoring, and evaluation and responds to a wider need to outline the working principles of WSAs in public health.

In search for successful overweight and obesity prevention, extensive research has shown that programs focused on individual behavior change are not effective enough. Many of the underlying determinants of overweight and obesity have social, environmental and economic origins, and extend even beyond the influence of the health sector and public health. This calls for a whole systems approach that covers a multi-sectoral, multi-stakeholder collaboration, where communities, professionals, government and industry are involved and are all part of the solution. The Amsterdam Healthy Weight Approach (AHWA), initiated in 2012, is a local government led approach that has the objective to encourage healthy weight for children in a healthy environment. With a long-term vision, aimed at lasting change, the AHWA aims at developing interventions, changing policies and educating and informing both professionals and target groups within the communities that are most heavily burdened with the issue of child obesity (and related complex health/wellbeing issues). The strength of the AHWA lies in adopting a whole systems approach (WSA), in which the key is, to collaborate in an integrated, multi-level, multi sectoral way, with a variety of stakeholders from within and outside the field of public health. The aim of the presentation is to inform participants from cities around the globe about the success factors, lessons learned and valuable elements of implementing the AHWA, and to provide tools which they can use in discussing their own approaches and bring these to a higher level of effectiveness

SamenvattingBij gamechangers in public health wordt vaak automatisch gedacht aan specifieke interventies of uitvindingen. Vroeger was dat het riool, later werden het vaccinaties en tegenwoordig gelden overspannen verwachtingen van leefstijlinterventies en (opnieuw) vaccinaties. Dit denken in termen van silver bullets heeft ons veel gebracht, maar loopt vast in de complexiteit van de huidige uitdagingen van de publieke gezondheid. In dit essay schetsen we het erkennen van en handelen vanuit die complexiteit als gamechanger. We beschrijven wat het denken in termen van complexiteit betekent voor de volksgezondheid, en wat dit vraagt van de publieke gezondheidszorg.