Relative cost-effectiveness

A key Summative Evaluation question is “How does the cost-effectiveness of this intervention compare to other interventions?” Some comparative metrics are:

Cost per averted incident

  • Intervention “x” cost £10,000 per averted incident.
  • Intervention “y” cost £1,000 per averted incident

Relative effectiveness

  • Intervention “x” reduced incidents by 50%.
  • Intervention “y” reduced incidents by 90%.

Relative durability

  • Intervention “x” reduced incidents per a period of three months.
  • Intervention “y” reduced incidents per a period of 20 years.

Scaling up

A common question to ask is whether it is feasible to increase the scale of an intervention. For example, a scheme that requires 5 full time staff (e.g. to perform school visits, roadshows and stakeholder collaboration) in relationship to one hotspot would require 500 staff if implemented in the top 100 hotspots in the UK. 

It is therefore only possible to scale up an intervention to this extent if it is deemed feasible to recruit and fund 500 staff nationwide.