Intervention logic
Go back to Section 32 - Methods of implementation
Intervention logic is not a new analytical tool but has recently become a popular way of demonstrating rigorous analysis. There are many different models for setting out intervention logic: these include, most commonly, matrices and flow diagrams.
There is no one right way to describe intervention logic. A common approach, however, is to set out the hierarchy of outcomes sought / anticipated beginning with the output, and including the immediate impact of a policy, any intermediate outcomes as well as the ultimate outcome.
Example: Regional Council A has a policy of promoting riparian revegetation to improve water quality. One of the methods used is a grant scheme which allocates funds to landowner-initiated riparian revegetation projects.
A simplified intervention logic for such a method might therefore be described as follows.
|
Output |
Immediate impact |
Intermediate outcome |
Ultimate outcome |
|---|---|---|---|---|
Outcome hierarchy |
Establishment of a fund to support riparian revegetation |
Increased rate of riparian fencing / planting |
Increased filtering/absorption of sediment and nutrients within riparian margins |
Reduced sediment and nutrient load in waterways |
Assumptions |
Community will support establishment of fund through the LTCCP process Sufficient funding can be budgeted to make the method effective |
A main obstacle to riparian planting is lack of private funding available There will be sufficient knowledge and uptake of the fund |
Fertiliser application rates remain the same Stocking rates and land use adjacent to riparian areas remains the same Landowners will maintain fences in good repair Riparian vegetation will have a good rate of survival Adequate pest and weed control will be carried out |
Main sources of sediment and nutrients are from diffuse discharges from agricultural land that has little or no riparian vegetation Increasing riparian planting will reduce diffuse discharges to waterways |
Risks (may include matters inside and outside council control) |
Budgetary constraints will compromise size of funding available Fund will be insufficient to meet demand, leading to disappointed landowners |
There will be no substantial take up of funding Other incentives to continue to farm riparian areas will prove a stronger influence on behaviour |
Land use economics change ushering in changes to more intensive land use leading to greater diffuse sources of sediment and nutrient than anticipated |
Other factors within the catchment (such as land clearance) will lead to levels of sediment and or nutrient that are beyond the ability or riparian buffers to mitigate |
The design of such an evaluation matrix will vary depending on the nature of the intervention (policy and method package).
A more sophisticated intervention description may include additional information including, for example:
- specific measures of success for each stage of the outcome hierarchy (including indicative time scale for when expected results will be achieved). For example, how many applications are received, what length of riparian margin is fenced and planted (as opposed to business as usual), what the anticipated reduction in sediment nutrient load will be in catchments where riparian planting has reached a prescribed level
- resources and activity that needs to be applied by councils at each stage - including what other parties will need to contribute/do in addition to the initiating council
- information requirements to measure success (what monitoring is required, what baseline information is required in order for progress to be demonstrated).
Note that many of these variables are valuable for subsequent (post-implementation) policy effectiveness evaluation.
