The build step turns a framed question and its evidence into a governed analytical product: versioned data, a model or pipeline with stated assumptions, and a record of who may run it and on what terms.
Fig.The Nexus cycle, from question to renewal. Design, not a record of a run.
Build is step three of the eight-step Nexus cycle: the step at which authorized projects build models, analysis and tools in Nexus Foundry. It is owned by Nexus Foundry. At this step GCRI runs Nexus Foundry, where authorized projects build models and analysis, and the decision at the end of the cycle stays with the competent authority.
Where people and networks concentrate, the exposure through which shocks travel between systems, shown for West Africa as an example geography for this subject.
A build in Nexus Foundry is not a dashboard. It is the set of inputs, code, parameters and outputs that produced a result, held so that a reviewer can rerun it and get the same answer, or see exactly why not. That is the reproducibility test applied to models used in public decisions, and the condition under which a finding can be corrected rather than argued about.
| Check | Reference practice |
|---|---|
| Model risk: purpose, limits, validation | Model risk management practice, read against ISO 31000 treatment of uncertainty |
| AI components | NIST AI RMF functions (govern, map, measure, manage) and ISO/IEC 42001 management-system controls |
| Information security | NIST CSF 2.0 functions, including the govern function added in version 2.0 |
| Data protection | Purpose limitation and minimisation under the applicable privacy law of the data's origin |
Who may build is set by an authorized project with an accountable owner. Access requests start at Nexus Foundry contact.
Each term as this page uses it. Where a standard-setting body defines the term, the wording follows that body.
| Term | Definition |
|---|---|
| Digital twin | A computational representation of a physical system that is updated with data from it and used to explore its behaviour. |
| Model validation | Comparing model predictions with independent observations to judge fitness for a stated use. |
| Provenance | Information about the entities, activities and people involved in producing a record, used to judge its quality and reliability, in the W3C PROV model. |
The bodies and documents this page is read against. Status and editions change; each link goes to the issuing body.
The current service level is R0: information and enquiries. An enquiry receives a reference and names the next step; applications, payments, compute allocations and registrations open only when their team, terms and review capacity exist.