FID (Final Investment Decision)

Final Investment Decision (FID) is the sanction gate at which a project sponsor formally commits the capital needed for execution. It is the most consequential single decision in the project lifecycle: up to FID, the project can be re-scoped, delayed, or cancelled with modest loss; after FID, the sponsor has made binding commitments to contracts, procurement and resources that are expensive to reverse. The analytical basis supporting FID — the FEED output, the QRA, the risk register, the contingency position — is therefore tested with particular rigour.

For the sponsor, FID is where the confidence level discussion matters most. The P80 cost and schedule position at FID becomes the baseline against which all subsequent performance is judged; the confidence range at FID determines what contingency is committed. An FID made on a weak QRA — one where the risk inputs are insufficiently calibrated, where correlation is mishandled, or where optimism bias is under-treated — commits the sponsor to an execution phase where the confidence position they thought they had is not the position they actually have.

UK major infrastructure programmes typically require multi-layered assurance before FID: internal sponsor review, external QRA assurance, IPA gateway review (for public-sector programmes), and in some sectors regulatory approval. Each layer tests the FEED output from a different angle. SOMA delivers independent QRA assurance specifically structured for FID support — reviewing the methodology, the risk register, the correlation treatment, and producing a defensible view of whether the headline confidence position is credible.