title: Interrupted Time Series Analysis coincidental intervention
body: <p>As part of our research we're conducted Controlled Interrupted Time Series Analysis on 35 individual case studies. In 33 instances the intervention occurs in isolation and can be analysed along standard lines. However, in 2 cases the intervention occurs alongside additional policy measures [that we do not have the data to replicate]. I had looked into methods, which suggested that one could account for coincident policies using an additional dummy variable, but am not sure I feel comfortable about such or really understand how to do so.</p>
  <p>Just wondered if people had a view in regards to the above and could explain/point me in the direction of research that outlines the technical elements in regards to code or the mathematical formulation?</p>
  <p>Any help hugely appreciated.
  Cheers</p>