Definition of a process
The DSP comprises six key process flows. Where a module supplies capability, a process is a stage of the decision itself.
What makes something a process
Each key process is defined by an interaction of modules and sub-processes that collectively generate an aggregated outcome.
That outcome then informs subsequent or preceding processes, which is what enables iterative refinement.
Note the word "preceding"
A process output can travel backwards as well as forwards. Evidence produced at option assessment can send you back to reframe the problem. The DSP is drawn left to right, but it is not required to run that way.
The six process flows
1. Asset and network evaluation
Develops an understanding of how the system currently functions, and establishes a baseline understanding of:
- Condition
- Capacity
- Constraints
The constraints explicitly include infrastructure degradation and deterioration, and vulnerabilities created by climate change. This is the stage that produces the "as things stand" picture everything later is compared against.
2. Problem framing and scope
Sets objectives and scope by clearly identifying what needs to be adapted and why. Three kinds of boundary get drawn here.
| Boundary | What gets fixed | Examples from the handbook |
|---|---|---|
| Geographic scope | Where the question applies | A specific rail corridor, a coastal zone, an urban catchment |
| Temporal horizons | How far ahead it looks | 2050, 2080, or 2100 |
| Assets or services | What is in scope | The assets or services required |
Alongside the boundaries, the stage captures two things about the world the decision sits in:
| Covering | |
|---|---|
| External factors | Stakeholder needs, policy environment, socio-economic conditions |
| Constraints | Budget, technical feasibility, environmental restrictions, political considerations |
Political considerations are named explicitly
The handbook lists political considerations as a constraint alongside budget and feasibility. Treating them as a constraint to be recorded, rather than an embarrassment to be worked around, is what allows a decision to be traced honestly afterwards.
3. Risk reduction analysis
Applies screening criteria to filter the long list down to a short list of options for detailed pathway development. The screening is informed by the risk and resilience assessment.
This stage also identifies and inputs thresholds and tipping points, the levels beyond which an asset or service stops performing acceptably.
4. Detailed option assessment
Involves a criteria selection process, followed by detailed development and assessment of the shortlisted options or pathways.
The source also refers to this stage as cost-benefit and multi-criteria analysis, which describes the two techniques it runs.
5. Portfolio optimisation
Looks at combining and sequencing multiple interventions or pathways, in order to use and bundle resources where possible.
The shift here is from judging options one at a time to judging them as a set. Two interventions that are each marginal alone can be worth doing together if they share a road closure, a design team or a supply chain.
6. Outcome assessment
Evaluates the effectiveness of interventions, and feeds learning back into the decision cycle and into future decisions.
How processes and modules relate
A process is not a container for modules. It is a stage that calls on them, and the same module serves several stages. The master diagram shows which module each stage draws on.
An inconsistency in the source
Three processes are named two different ways
The source handbook lists the six process names in one form, then uses different names for three of them in the detailed descriptions.
| Used in headings and lists | Used in the detailed descriptions |
|---|---|
| Problem framing and scope | Problem Framing and Context |
| Risk reduction analysis | Risk Reduction Needs |
| Detailed option assessment | Cost-benefit / multi-criteria analysis |
The other three, asset and network evaluation, portfolio optimisation and outcome assessment, are consistent.
This handbook uses the first column throughout, because those are the names the source's own chapter headings use in Technical processes. The alternatives are noted where they add meaning, since "cost-benefit and multi-criteria analysis" does describe what stage four actually does.