Complex interventions or complex systems? Implications for health economic evaluation

Although guidelines exist for evaluating complex interventions, they may be of little help in dealing with the multiple effects of interventions in complex systems such as hospitals. Alan Shiell, Penelope Hawe, and Lisa Gold explain why it is important to distinguish the two types of complexity

• FP
  Fondation pour la Recherche Médicale
• CI
  Canadian Institutes of Health Research
• MR
  Medical Research Council