Moerbeek Mirjam
Department of Methodology and Statistics, Utrecht University, Utrecht, the Netherlands.
Stat Methods Med Res. 2020 Mar;29(3):797-810. doi: 10.1177/0962280219846149. Epub 2019 May 1.
With group randomized trials complete groups of subject are randomized to treatment conditions. Such grouping also occurs in individually randomized trials where treatment is administered in groups. Outcomes may be measured at the level of the subject, but also at the level of the group. The optimal design determines the number of groups and the number of subjects per group in the intervention and control conditions. It is found by taking a budgetary constraint into account, where costs are associated with implementing the intervention and control, and with taking measurements on subject and groups. The optimal design is found such that the effect of treatment is estimated with highest efficiency, and the total costs do not exceed the budget that is available. The design that is optimal for the outcome at the subject level is not necessarily optimal for the outcome at the group level. Multiple-objective optimal designs consider both outcomes simultaneously. Their aim is to find a design that has high efficiencies for both outcome measures. An Internet application for finding the multiple-objective optimal design is demonstrated on the basis of an example from smoking prevention in primary education, and another example on consultation time in primary care.
在成组随机试验中，将受试对象分组并随机分配至各治疗条件。这种分组也会出现在个体随机试验中，即治疗以组为单位进行。结局可在个体水平进行测量，也可在组水平进行测量。最优设计确定了干预组和对照组的组数以及每组的受试对象数量。它是通过考虑预算限制得出的，其中成本与实施干预和对照以及对个体和组进行测量相关。找到最优设计是为了以最高效率估计治疗效果，且总成本不超过可用预算。在个体水平对结局最优的设计不一定在组水平对结局也是最优的。多目标最优设计同时考虑两种结局。其目的是找到一种对两种结局测量都具有高效率的设计。基于小学预防吸烟的一个例子以及初级保健中咨询时间的另一个例子，展示了一个用于寻找多目标最优设计的互联网应用程序。
