Thorn Joanna, Coast Joanna, Andronis Lazaros
School of Social and Community Medicine, University of Bristol, Bristol, South West England, UK (JT)
Health Economics Unit, University of Birmingham, Birmingham, West Midlands, UK (JC, LA)
Med Decis Making. 2016 Apr;36(3):285-95. doi: 10.1177/0272989X15586552. Epub 2015 May 18.
Expected value of perfect information (EVPI) calculations are increasingly performed to guide and underpin research recommendations. An EVPI value that exceeds the estimated cost of research forms a necessary (although not sufficient) condition for further research to be considered worthwhile. However, it is unclear what factors affect researchers' recommendations and whether there is a notional threshold of positive returns below which research is not recommended. The objectives of this study were to explore whether EVPI and other factors have a bearing on research recommendations and to assess whether there exists a threshold EVPI below which research is typically not recommended.
A systematic literature review was undertaken to identify applied EVPI calculations in the health care field. Study characteristics were extracted, including funder, location, disease group, publication year, primary language, and outcome measure. Population EVPI values and willingness-to-pay thresholds were also extracted alongside verbatim text excerpts describing the authors' research recommendations. Recommendations were classified according to whether further research was recommended (a positive recommendation) or not (negative). Factors affecting the likelihood of a positive recommendation were examined statistically using logistic regression and visually by plotting the results in graphs.
Eighty-six articles were included, of which 13 suggested no further research, 66 recommended further research, and 7 gave no recommendation. EVPI appears to be a key driver of researchers' recommendations for further research. Disease area, funder, study location, publication year, and outcome may have a bearing on recommendations, although none of these factors reached statistical significance. A threshold EVPI value below which research is typically not recommended was found at around £ 1.48 million.
越来越多地进行完全信息期望值（EVPI）计算，以指导和支持研究建议。一个超过研究估计成本的EVPI值构成了进一步研究被认为值得的必要条件（尽管不是充分条件）。然而，尚不清楚哪些因素会影响研究人员的建议，以及是否存在一个名义上的正回报阈值，低于该阈值则不建议进行研究。本研究的目的是探讨EVPI和其他因素是否对研究建议有影响，并评估是否存在一个阈值EVPI，低于该阈值通常不建议进行研究。
进行了一项系统的文献综述，以确定医疗保健领域中应用的EVPI计算。提取了研究特征，包括资助者、地点、疾病组、出版年份、主要语言和结果指标。还提取了总体EVPI值和支付意愿阈值，以及描述作者研究建议的逐字文本摘录。根据是否建议进一步研究（肯定建议）或不建议（否定建议）对建议进行分类。使用逻辑回归统计检验影响肯定建议可能性的因素，并通过将结果绘制成图表直观地进行分析。
纳入了86篇文章，其中13篇建议不再进行进一步研究，66篇建议进一步研究，7篇未给出建议。EVPI似乎是研究人员建议进一步研究的关键驱动因素。疾病领域、资助者、研究地点、出版年份和结果可能对建议有影响，尽管这些因素均未达到统计学意义。发现一个阈值EVPI值约为148万英镑，低于该值通常不建议进行研究。
