Public Health Nutrition Research Group, University of Aberdeen, Polwarth Building, Foresterhill, Aberdeen AB252ZD, United Kingdom.
Soc Sci Med. 2010 Mar;70(5):769-78. doi: 10.1016/j.socscimed.2009.10.067. Epub 2009 Dec 11.
In a cluster randomised controlled trial of a policy to provide community breastfeeding support groups in Scotland, breastfeeding rates declined in 3 of 7 intervention localities. From a preliminary study, we expected breastfeeding outcomes to vary and we prospectively used qualitative and quantitative methods to ask why. Ethnographic in-depth interviews, focus groups, observations and survey data were analysed to build seven embedded case studies. A pyramidal model of how primary health service organisations implemented the policy was constructed prior to knowing trial outcomes to minimise bias. Informed by a realist approach, the model explained variation in (a) policy implementation (b) the breastfeeding outcomes, whereas the quantity of intervention delivered did not. In the three localities where breastfeeding rates declined, negative aspects of place including deprivation, unsuitable premises and geographical barriers to inter-professional communication; personnel resources including staff shortages, high workload and low morale; and organisational change predominated (the base model tiers). Managers focused on solving these problems rather than delivering the policy and evidence of progress to the higher model tiers was weak. In contrast, where breastfeeding rates increased the base tiers of the model were less problematic, there was more evidence of leadership, focus on the policy, multi-disciplinary partnership working and reflective action cycles (the higher model tiers). We advocate an ethnographic approach to the design and evaluation of complex intervention trials and illustrate how this can assist in developing an explanatory model. More attention should be given to the complex systems within which policies and interventions occur, to identify and understand the favourable conditions necessary for a successful intervention.
在苏格兰一项针对提供社区母乳喂养支持小组政策的整群随机对照试验中，7 个干预地点中有 3 个地区的母乳喂养率下降。根据初步研究，我们预计母乳喂养结果会有所不同，因此前瞻性地使用定性和定量方法来探究原因。采用人种学深入访谈、焦点小组、观察和调查数据进行分析，构建了 7 个嵌入式案例研究。在了解试验结果之前，构建了一个初级卫生服务组织实施该政策的金字塔模型，以尽量减少偏差。该模型受现实主义方法的启发，解释了（a）政策实施（b）母乳喂养结果的变化，而干预措施的数量并不能解释这些变化。在母乳喂养率下降的 3 个地区，包括贫困、不适合的场所和跨专业沟通的地理障碍等负面的地方因素；人员资源包括人员短缺、工作量大、士气低落；以及组织变革占据主导地位（基础模型层次）。管理人员专注于解决这些问题，而不是执行政策并向更高层次的模型提供进展情况的证据，这方面的证据很薄弱。相比之下，母乳喂养率上升的地区，基础模型层次的问题较少，领导层、对政策的关注、多学科伙伴关系以及反思行动循环的证据较多（更高层次的模型）。我们提倡在复杂干预试验的设计和评估中采用人种学方法，并举例说明了这如何有助于开发解释模型。应更加关注政策和干预措施发生的复杂系统，以确定和理解成功干预所需的有利条件。
