The importance and need for SWAT coordination

Background Studies Within A Trial (SWATs) provide evidence for trial process decisions by evaluating alternative trial processes or exploring why processes are undertaken. SWATs can be undertaken as: ‘Individual’, ‘Individually with Coordination’ and ‘Coordinated Simultaneous’. Using these approaches efficiently can facilitate timely and definitive identification of effective and ineffective trial processes, however this rarely happens. This paper compares the three approaches and offers guidance on how to use these efficiently. Methods Using direct experience of undertaking SWATs and data collected during the PROMETHEUS programme, the advantages and disadvantages of each SWAT approach were identified and summarised. Results ‘Individual’ SWATs are best for simple strategies or where flexibility is needed. They do not usually reach a definitive conclusion meaning replications and meta-analysis are required. This enables replication in a range of populations but requires significant time to reach a conclusion. SWATs conducted ‘individually with coordination’ are like both ‘individual’ and ‘coordinated simultaneous’ SWATs. Coordination helps evidence accumulate more quickly, reduces intervention heterogeneity, and enables replications in specific populations; however, coordination can be difficult to facilitate. For ‘Coordinated simultaneous’ SWATs, the same intervention is evaluated at the same time in multiple trials enabling ascertainment of effectiveness in a single evaluation. Data must be combined and analysed promptly, requiring a dedicated team to manage SWAT conduct. Conclusion Undertaking SWATs as ‘individual’, ‘individually with coordination’ or ‘coordinated simultaneous’ depends on the host trial, research team preferences, resources, and the proposed SWAT. A combination of approaches may be required to reach a definitive conclusion. Key words: Study Within A Trial; SWAT; Embedded randomised controlled trial; Trial methodology; Sub-study