Accounting for complexity in critical realist trials: the promise of PLS-SEM

Background: Randomized controlled trials have been criticized for their inability to identify and differentiate the causal mechanisms that generate the outcomes they measure. One solution is the development of realist trials that combine the empirical precision of trials' outcome data with realism's theoretical capacity to identify the powers that generate outcomes. Main Body: We review arguments for and against this position and conclude that critical realist trials are viable. Using the example of an evaluation of the educational effectiveness of virtual reality simulation, we explore whether Partial Least Squares Structural Equation Modelling can move statistical analysis beyond correlational analysis to support realist identification of the mechanisms that generate correlations. Conclusion: We tentatively conclude that PLS-SEM, with its ability to identify ‘points of action’, has the potential to provide direction for researchers and practitioners in terms of how, for whom, when, where and in what circumstances an intervention has worked.