Centre for Evaluation, London School of Hygiene and Tropical Medicine, Keppel Street, London, WC1E 7HT, UK.
Centre for Sexual Health and HIV/AIDS Research (CeSHHAR) Zimbabwe, 4 Bath Road, Harare, Zimbabwe.
Trials. 2024 Nov 18;25(1):777. doi: 10.1186/s13063-024-08623-7.
Process evaluations are increasingly integrated into randomised controlled trials (RCTs) of complex interventions to document their delivery and interactions with local systems and dynamics, helping understand observed health outcomes. Yet process evaluations often struggle to assess relevant contextual determinants, leaving much of the important role of "context" in shaping an intervention's mechanisms opaque in many studies. A lack of easily adapted data collection methods to help define and operationalise indicators of context likely contributes to this.
We present a method to help structure measures of context in process evaluations and describe its use in two very different settings. The "Context Tracker" is an innovative tool for use within trials and quasi-experiments to more systematically capture and understand key dimensions of context. It was developed in Zimbabwe as part of a cluster randomised controlled trial and then adapted for a quasi-experimental evaluation in the UK. Both studies provided harm reduction and health services for marginalised and hard-to-reach populations.
We developed the Context Tracker to be both standardised (i.e. formatted and applied in the same way across study sites) and flexible enough to allow unique features to be explored in greater detail. Drawing on the Context and Implementation of Complex Interventions (CICI) and Risk Environments frameworks, we mapped 5 domains across micro, meso and macro levels in a simple table and used existing evidence and experience to predict factors likely to affect delivery of and participation in intervention components. We tracked these over time across study sites using routine programme statistics, observation and qualitative methods. The Context Tracker enables identification and comparison of facilitators and barriers to implementation, variations in engagement with interventions, and how mechanisms of action are (or are not) triggered in different settings.
The Context Tracker is one example of how evidence-based contextual determinants can be used to guide data collection and analysis within process evaluations. It is relevant in low- and high-income settings and applicable to both qualitative and quantitative analyses. While perhaps most useful to process evaluations of complex interventions targeting marginalised communities, the broader approach would benefit a more general research audience.
过程评估越来越多地被纳入复杂干预措施的随机对照试验（RCT）中，以记录其实施情况以及与当地系统和动态的相互作用，从而帮助了解观察到的健康结果。然而，过程评估往往难以评估相关的情境决定因素，使得许多研究中干预措施机制的“情境”重要作用不透明。缺乏易于适应的数据收集方法来帮助定义和操作情境指标可能是造成这种情况的原因之一。
我们提出了一种帮助构建过程评估中情境衡量标准的方法，并描述了它在两个非常不同的环境中的使用。“情境追踪器”是一种创新的工具，可用于试验和准实验中，以更系统地捕捉和理解情境的关键维度。它是在津巴布韦开发的，作为一项集群随机对照试验的一部分，然后在英国的一项准实验评估中进行了改编。这两项研究都为边缘化和难以接触到的人群提供了减少伤害和卫生服务。
我们开发了“情境追踪器”，使其既标准化（即在研究地点以相同的方式格式化和应用）又灵活，足以更详细地探索独特的特征。我们借鉴了复杂干预措施的情境和实施（CICI）以及风险环境框架，在一个简单的表格中绘制了微观、中观和宏观层面的 5 个领域，并利用现有证据和经验预测了可能影响干预措施组件的实施和参与的因素。我们使用常规计划统计数据、观察和定性方法来跟踪这些因素在研究地点随时间的变化。“情境追踪器”能够识别和比较实施的促进因素和障碍、与干预措施的不同参与程度，以及在不同环境中如何触发作用机制。
“情境追踪器”是一种如何使用基于证据的情境决定因素来指导过程评估中数据收集和分析的示例。它在低收入和高收入环境中都适用，适用于定性和定量分析。虽然它对针对边缘化社区的复杂干预措施的过程评估最有用，但更广泛的方法将使更一般的研究受众受益。
