What is an adequate sample size? Operationalising data saturation for theory-based interview studies
What is an adequate sample size? Operationalising data saturation for theory-based interview studies
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DOI：
10.1080/08870440903194015
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发表时间：
2010-01-01
影响因子：
3.3
通讯作者：
Grimshaw, Jeremy M.
中科院分区：
文献类型：
--
作者：
Francis, Jill J.;Johnston, Marie;Grimshaw, Jeremy M.
在访谈研究中，样本大小通常是通过对参与者进行访谈直到达到“数据饱和”来确定的。然而，目前还没有达成一致的方法来确立这一点。在基于理论的访谈研究中，我们提出了确定饱和度的原则(其中概念范畴是由现有理论预先确定的)。首先，指定初始分析的最小样本量(初始分析样本)。其次，具体说明将进行多少次没有新想法出现的面试(停止标准)。我们在两项研究中展示了这些原则，这两项研究基于计划行为理论，旨在确定三种信念类别(行为、规范和控制)，使用10个初始分析样本和3个停止标准。研究1(现有数据的回顾分析)确定了14名全科医生关于在不开抗生素的情况下处理喉咙痛患者的84种共同信念。标准信念达到了饱和标准，但其他信念或学习饱和没有达到标准。在研究2(前瞻性分析)中，17名骨佩吉特氏病患者的亲属报告了44种关于接受基因测试的共同信念。研究性的数据饱和是在访谈17中实现的。我们提出了在基于理论的访谈研究中报告数据饱和的这些原则的规范。这些原则可能适用于其他类型的研究。
In interview studies, sample size is often justified by interviewing participants until reaching 'data saturation'. However, there is no agreed method of establishing this. We propose principles for deciding saturation in theory-based interview studies (where conceptual categories are pre-established by existing theory). First, specify a minimum sample size for initial analysis (initial analysis sample). Second, specify how many more interviews will be conducted without new ideas emerging (stopping criterion). We demonstrate these principles in two studies, based on the theory of planned behaviour, designed to identify three belief categories (Behavioural, Normative and Control), using an initial analysis sample of 10 and stopping criterion of 3. Study 1 (retrospective analysis of existing data) identified 84 shared beliefs of 14 general medical practitioners about managing patients with sore throat without prescribing antibiotics. The criterion for saturation was achieved for Normative beliefs but not for other beliefs or studywise saturation. In Study 2 (prospective analysis), 17 relatives of people with Paget's disease of the bone reported 44 shared beliefs about taking genetic testing. Studywise data saturation was achieved at interview 17. We propose specification of these principles for reporting data saturation in theory-based interview studies. The principles may be adaptable for other types of studies.