Working methodology · working-0.1

How the estimate is built.

The model starts with provider-level STEM postgraduate research populations. It then applies a fixed estimated Student-visa share and two visible working assumptions.

The calculation

Selected UK STEM PGR population × estimated Student-visa share × startup-idea exploration rate × traction/incorporation rate.

Value status

Working assumptions on UK PGRs

Current data status

The provider population comes from the imported HESA 2024/25 files. Sector-specific non-UK values remain modelled because the open four-way cross-tab is unavailable. Documented disclosure control and approval of every default assumption remain publication gates.

Sources under audit

Limitations

Public HESA subject data identify permanent address, not immigration permission. The fixed 40% value is therefore the published international share of STEM PGRs, used as the best available proxy rather than a direct count of Student-visa holders. Home Office sponsored-study releases provide course-level visa grants but not the current stock of STEM PGR visa holders. All outputs are estimates and carry uncertainty.