Complex intervention

Unlike my previously predicted focus for this last week I have attempted to focus on the challenges posed by the idea/concept of 'complex intervention'. The idea that health researchers use the notion of complexity to help them indicate the problems faced in evaluating the effectiveness of interventions which include far more varibles than those perhaps presented in a drug trial was not new to me. It seems only logical that when describing something with numerous components and possibilities the word 'complex' would appear. What was new to me was the 2 differing angles presented in literature such as that by Shiell, Hawe and Gold (2008). They explain that whilst yes interventions can be complex, there is an alternative viewpoint, that is that complexity is the property of a system not an intervention. That is, the idea that a system such as the human body or a school may be composed of numerous interventions and that by looking at the system as a whole one is able to establish an understanding of the the different relationships occuring between the different components or the different interventions. Currently in my mind, being able to contextualise the intervention and gauge a better understanding of the system occuring around it would allow the researcher to design/develop a more successful intervention, one that is appropriate and surely that through this understanding it would be possible to better appreciate what influences affected which feature of the intervention thus allowing for successful duplication of the intervention elsewhere with informed ,minor changes being made? This I have yet to read about but the next stage of this week will be getting to grips with the process of designing an intervention - what does it entail?
 So far I have understood that there are 5 stages:
pre-clinical theory -what has been done before? understanding the research that has gone before
modelling - identification of the key components or mechanisms
exploratory trial - tes of the actual trial - allowing changes to be made
the definitive trial
the long term implementation

I look forward to getting to grips with these and how the evaluation occurs!