Porter Sam, McConnell Tracey, Reid Joanne
Department of Social Sciences and Social Work, Bournemouth University, R203, Royal London House, Christchurch Road, BH1 3LT, Bournemouth, UK.
School of Nursing and Midwifery, Queen's University Belfast, Belfast, BT7 1NN, UK.
Trials. 2017 Mar 21;18(1):133. doi: 10.1186/s13063-017-1855-1.
Some realists have criticised randomised controlled trials for their inability to explain the causal relations that they identify; to take into account the influence of the social context of the interventions they evaluate; and to account for individual difference. However, among realists, there is controversy over whether it is possible to improve trials by making them realist, or whether realism and the philosophical assumptions underlying trials are incompatible. This paper contributes to the debate in Trials on this issue. The debate thus far has concentrated on the possibility of combining trial methodology with that of realist evaluation.
We concur with the contention that it is not feasible to combine randomised controlled trial design with the realist evaluation approach. However, we argue that a different variant of realism, critical realism, provides a more appropriate theoretical grounding for realist trials. In contrast to realist evaluation, which regards social mechanisms as an amalgam of social resources and people's reasoning, critical realism insists on their distinction. It does so on the basis of its assertion of the need to distinguish between social structures (in which resources lie) and human agency (which is at least partly guided by reasoning). From this perspective, conceiving of social mechanisms as external to participants can be seen as a valid methodological strategy for supplementing the exclusive concentration of trials on outcomes. While accepting realist evaluation's insistence that causality in open systems involves a configuration of multiple generative mechanisms, we adopt the critical realist interpretation of the experimental method, which sees it as creating artificial closure in order to identify the effects of specific causal mechanisms. If randomised controlled trials can be regarded as epidemiological proxies that substitute probabilistic controls over extraneous factors for closed experiments, their examination of the powers of discrete mechanisms through observation of the variation of outcomes is appropriate.
While there are still issues to be resolved, critical realist randomised controlled trials are possible and have the potential to overcome some of the difficulties faced by traditional trial designs in accounting for the influence of social context and individual interpretation.
一些实在论者批评随机对照试验无法解释其所确定的因果关系；无法考虑其所评估干预措施的社会背景影响；也无法顾及个体差异。然而，在实在论者中，对于是否有可能通过使试验具有实在论性质来改进试验，或者实在论与试验所基于的哲学假设是否不相容，存在争议。本文为《试验》杂志上关于这一问题的辩论做出了贡献。迄今为止的辩论主要集中在将试验方法与实在论评价方法相结合的可能性上。
我们认同将随机对照试验设计与实在论评价方法相结合是不可行的这一观点。然而，我们认为，实在论的一种不同变体——批判实在论，为实在论试验提供了更合适的理论基础。与将社会机制视为社会资源与人们推理的混合体的实在论评价不同，批判实在论坚持对它们进行区分。这样做是基于其主张有必要区分社会结构（资源所在之处）和人类能动性（至少部分受推理引导）。从这个角度来看，将社会机制视为参与者外部的因素可被视为一种有效的方法论策略，以补充试验对结果的排他性关注。在接受实在论评价所坚持的开放系统中的因果关系涉及多种生成机制配置的观点的同时，我们采用批判实在论对实验方法的解释，即认为实验方法是创造人为的封闭状态以识别特定因果机制的效果。如果随机对照试验可被视为通过对外部因素进行概率控制来替代封闭实验的流行病学替代方法，那么通过观察结果变化来检验离散机制的效力是合适的。
虽然仍有一些问题有待解决，但批判实在论随机对照试验是可行的，并且有可能克服传统试验设计在考虑社会背景和个体解读影响方面所面临的一些困难。
