%V 5 %P 26-33 %D 2015 %C England %N 1 %K Health Economics, Methodological Research, Palliative Care, Research Design, Terminal Care %T Evaluating a complex system-wide intervention using the difference in differences method: the Delivering Choice Programme. %X We report the use of difference in differences (DiD) methodology to evaluate a complex, system-wide healthcare intervention. We use the worked example of evaluating the Marie Curie Delivering Choice Programme (DCP) for advanced illness in a large urban healthcare economy. %L discovery1403052 %J BMJ Supportive & Palliative Care %A J Round %A R Drake %A E Kendall %A R Addicott %A N Agelopoulos %A L Jones %O This is an Open Access article distributed in accordance with the Creative Commons Attribution Non Commercial (CC BY-NC 3.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See: http://creativecommons.org/licenses/by-nc/3.0/