Careful consideration and planning are required to establish “sufficient” evidence to ensure an investment in a larger, more well-powered behavioral intervention trial is worthwhile. In the behavioral sciences, this process typically occurs where smaller-scale studies inform larger-scale trials. Believing that one can do the same things and expect the same outcomes in a larger-scale trial that were done in a smaller-scale preliminary study (i.e., pilot/feasibility) is wishful thinking, yet common practice. Starting small makes sense, but small studies come with big decisions that can influence the usefulness of the evidence designed to inform decisions about moving forward with a larger-scale trial. The purpose of this commentary is to discuss what may constitute sufficient evidence for moving forward to a definitive trial. The discussion focuses on challenges often encountered when conducting pilot/feasibility studies, referred to as common (mis)steps, that can lead to inflated estimates of both feasibility and efficacy, and how the intentional design and execution of one or more, often small, pilot/feasibility studies can play a central role in developing an intervention that scales beyond a highly localized context. Establishing sufficient evidence to support larger-scale, definitive trials, from smaller studies, is complicated. For any given behavioral intervention, the type and amount of evidence necessary to be deemed sufficient is inherently variable and can range anywhere from qualitative interviews of individuals representative of the target population to a small-scale randomized trial that mimics the anticipated larger-scale trial. Major challenges and common (mis)steps in the execution of pilot/feasibility studies discussed are those focused on selecting the right sample size, issues with scaling, adaptations and their influence on the preliminary feasibility and efficacy estimates observed, as well as the growing pains of progressing from small to large samples. Finally, funding and resource constraints for conducting informative pilot/feasibility study(ies) are discussed. Sufficient evidence to scale will always remain in the eye of the beholder. An understanding of how to design informative small pilot/feasibility studies can assist in speeding up incremental science (where everything needs to be piloted) while slowing down premature scale-up (where any evidence is sufficient for scaling).

中文翻译：

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小研究，大决定：试点/可行性研究在增量科学和行为干预的过早扩大中的作用

需要仔细考虑和计划以建立“足够”的证据，以确保对更大、更有力的行为干预试验的投资是值得的。在行为科学中，这个过程通常发生在小规模研究为大规模试验提供信息的地方。相信人们可以在更大规模的试验中做与在较小规模的初步研究（即试点/可行性）中所做的相同的事情并期望获得相同的结果是一厢情愿的想法，但却是普遍的做法。从小处着手是有道理的，但小型研究伴随着重大决定，这些决定可能会影响证据的有用性，这些证据旨在为有关推进更大规模试验的决定提供信息。这篇评论的目的是讨论什么可能构成足够的证据来推进最终审判。讨论的重点是进行试点/可行性研究时经常遇到的挑战，称为常见（错误）步骤，可能导致对可行性和有效性的夸大估计，以及如何有意设计和执行一个或多个（通常是小的），试点/可行性研究可以在制定超越高度本地化背景的干预措施方面发挥核心作用。从较小的研究中建立足够的证据来支持更大规模、确定性的试验是很复杂的。对于任何给定的行为干预，被认为足够的必要证据的类型和数量本质上是可变的，范围可以从对代表目标人群的个人的定性访谈到模拟预期的更大规模试验的小规模随机试验。所讨论的试点/可行性研究执行过程中的主要挑战和常见（错误）步骤集中于选择正确的样本量、缩放问题、适应及其对观察到的初步可行性和功效估计的影响，以及成长的烦恼从小样本到大样本。最后，讨论了开展信息试点/可行性研究的资金和资源限制。足够的规模证据将永远留在旁观者的眼中。了解如何设计信息丰富的小型试点/可行性研究可以帮助加快增量科学（一切都需要试点），同时减缓过早的扩大（任何证据都足以扩大规模）。