“Simple” interventions | “Complex” interventions | |
---|---|---|
Population | Sick population seeking care | Healthy general or at-risk population |
Intervention | Individual-level intervention | Population- and/or individual-level intervention |
Single component | Multiple interacting components | |
“Reactive” treatment through medication or surgery or clinical prevention | “Proactive” prevention through behaviour change and/or technical intervention and/or policy | |
Implementation in healthcare setting | Implementation in household, community or policy setting | |
Comparison | No intervention or alternative intervention through treatment/surgery | “Business as usual” in several sectors |
Outcome | Shorter causal pathway | Longer causal pathway |
One or a small number of health outcomes | Multiple health outcomes and broader societal consequences | |
Usually impact after short lag period | Usually impact after long lag period | |
Delivery of intervention | Delivery through health sector | Delivery through multiple sectors |
Contextual effects | Variation between healthcare providers (individuals, institutions) | Variation between providers of different intervention components in multiple sectors |
Patient preference and compliance | Large cultural and behavioural variation |