The minimum sample size for multistakeholder Delphi surveys remains understudied. Drawing from three large international multistakeholder Delphi surveys, this study aimed to: 1) investigate the effect of increasing sample size on replicability of results; 2) assess whether the level of replicability of results differed with participant characteristics: for example, gender, age, and profession. We used data from Delphi surveys to develop guidance for improved reporting of health-care intervention trials: SPIRIT (Standard Protocol Items: Recommendations for Interventional Trials) and CONSORT (Consolidated Standards of Reporting Trials) extension for surrogate end points ( = 175, 22 items rated); CONSORT-SPI [CONSORT extension for Social and Psychological Interventions] ( = 333, 77 items rated); and core outcome set for burn care ( = 553, 88 items rated). Resampling with replacement was used to draw random subsamples from the participant data set in each of the three surveys. For each subsample, the median value of all rated survey items was calculated and compared to the medians from the full participant data set. The median number (and interquartile range) of medians replicated was used to calculate the percentage replicability (and variability). High replicability was defined as ≥80% and moderate as 60% and <80% The average median replicability (variability) as a percentage of total number of items rated from the three datasets was 81% (10%) at a sample size of 60. In one of the datasets (CONSORT-SPI), a ≥80% replicability was reached at a sample size of 80. On average, increasing the sample size from 80 to 160 increased the replicability of results by a further 3% and reduced variability by 1%. For subgroup analysis based on participant characteristics (eg, gender, age, professional role), using resampled samples of 20 to 100 showed that a sample size of 20 to 30 resulted to moderate replicability levels of 64% to 77%. We found that a minimum sample size of 60–80 participants in multistakeholder Delphi surveys provides a high level of replicability (≥80%) in the results. For Delphi studies limited to individual stakeholder groups (such as researchers, clinicians, patients), a sample size of 20 to 30 per group may be sufficient.

中文翻译：

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多利益相关方 Delphi 调查中的样本量：结果的可复制性在什么最小样本量下稳定？


多利益相关方 Delphi 调查的最小样本量仍未得到充分研究。本研究借鉴了三项大型国际多利益相关方 Delphi 调查，旨在：1） 调查增加样本量对结果可复制性的影响;2） 评估结果的可复制性水平是否与参与者的特征不同：例如，性别、年龄和职业。我们使用来自 Delphi 调查的数据来制定改进医疗保健干预试验报告的指南：替代终点的 SPIRIT（标准方案项目：干预试验建议）和 CONSORT（报告试验综合标准）扩展（= 175,22 个评级项目）;CONSORT-SPI [CONSORT extension for Social and Psychological Interventions] （ = 333,77 个项目评级）;和烧伤护理的核心结果集（= 553,88 个评分项目）。使用带替换的重采样从三项调查中每一项的参与者数据集中抽取随机子样本。对于每个子样本，计算所有评级调查项目的中位数，并与完整参与者数据集的中位数进行比较。复制的中位数 （和四分位数范围） 用于计算百分比可重复性 （和可变性）。高复制性定义为 ≥80%，中等定义为 60% 和 <80% 在样本量为 60 时，三个数据集中评分项目总数的平均中位数（可变性）百分比为 81% （10%）。在其中一个数据集 （CONSORT-SPI） 中，在 80 个样本量下达到了 ≥80% 的可复制性。平均而言，将样本量从 80 个增加到 160 个，结果的可重复性进一步提高了 3%，变异性降低了 1%。 对于基于参与者特征（例如，性别、年龄、专业角色）的亚组分析，使用 20 至 100 的重新采样样本表明，20 至 30 的样本量导致 64% 至 77% 的中等可复制性水平。我们发现，在多利益相关方 Delphi 调查中，至少 60-80 名参与者的样本量提供了高水平的结果可复制性 （≥80%）。对于仅限于个体利益相关者群体（如研究人员、临床医生、患者）的 Delphi 研究，每组 20 至 30 个样本量可能就足够了。