Abstract: The use of qualitative methods in general practice research has important practical significance，which can better reflect the features of patient-centered care and promote the development of primary health care services. Qualitative research in general practice has reached a relatively mature stage in foreign countries，but it is still in a preliminary stage in China，and many practical problems will be encountered when conducting relevant studies，among them，a common problem is about sample size. However，there is no a standard answer to it. In general，the depth and breadth in one study are interdependent. As qualitative research focuses on a deeper and more detailed understanding of the research phenomenon，it is generally believed that the richness of data in qualitative research is far more important than the number of samples，and the sample size needs not to be too large. However，the sample size and its related reference dimensions still need to be considered when writing a qualitative research proposal. This article introduces the estimation of the sample size of qualitative interviews based on information power，to provide a reference for qualitative researchers.

Key words: General practice, Qualitative research, Sample size, Information power

摘要： 在全科医学领域应用定性研究，可以更好地体现以患者为中心的医疗模式，促进基层医疗卫生服务发展，具有重要的实践意义。目前国外在全科医学领域应用定性研究已经比较成熟，而国内尚处于早期发展阶段。因此，在开展定性研究的过程中会碰到很多实际的操作问题，其中一个常见问题就是样本量的问题。但是，对于定性研究的样本量，没有人能给出一个标准答案。总体来说，一项研究的深度和广度是相互制约的。由于定性研究注重对研究现象进行比较深入、细致的理解，通常认为定性研究中资料的丰富程度远比样本的数量重要，但是在撰写定性研究计划时，样本量仍然需要提前考虑。定性研究的样本量需要考量研究所涉及的与样本量有关的维度。本文介绍基于信息效能模型考虑定性访谈的样本量，为定性研究者初步拟定访谈对象的数量提供参考依据。

关键词: 全科医学, 质性研究, 样本量, 信息效能