PURCHASE METHOD ADVISOR

↳ Companion to: Digital Procurement Training | LASS TECH
Follow-On Guide

Purchase Method Reference

Five primary procurement routes, each suited to different equipment types, market conditions, and strategic contexts. Select a card for detailed guidance.

Government-to-Government (G-G)

State-to-state agreement bypassing commercial competition. Leveraged for allied military equipment, classified technology transfer, or where FMS/DCS regimes apply.

No Competition Military / Dual-Use High Sovereignty Risk

Framework Contract

Pre-qualified panel of suppliers; call-off contracts placed over an agreed term. Ideal for recurring consumables, sustainment services, and spares supply chains.

Pre-Competed Repeat Buys Medium Flexibility

Direct Contract (Single Source)

Award to a sole supplier without competition. Justified by OEM exclusivity, urgency, or where only one source can satisfy the technical requirement.

Single Source Requires Justification Cost Risk ↑

Closed / Restricted Competition

Invitation to a shortlisted set of pre-qualified vendors. Used for classified programmes, niche capability domains, or when only a small market can respond.

Shortlisted Classified / Sensitive Faster Cycle

Open Competition

Unrestricted tender to the market. Maximises value for money, encourages new entrants and innovation. Required by most public procurement regulations above threshold.

Max Competition Regulatory Default Longer Cycle
Complementary tool note: This guide advises on how to buy. The Digital Procurement Training tool advises on what contract type to use once the method is selected (FFP, CPIF, CPFF…). Use both together for a complete procurement strategy.

Method Selection by Equipment Category

View by:

Purchase Method Wizard

Answer the questions below to receive a tailored purchase method recommendation with contract type, pricing model, and risk guidance.

00 · Qualifier
01 · Equipment
02 · Market
03 · Classification
04 · Budget
05 · Urgency
Result
Qualifier — What is the primary trigger for this procurement?

The procurement trigger determines which constraints are active from the outset — IP ownership, incumbent suppliers, urgency authorities, and certification regimes all depend on this answer before any other question is relevant.

1 / 5 — What category best describes the equipment?
2 / 5 — How many qualified suppliers exist in the global market?
3 / 5 — What is the security / export control sensitivity?
4 / 5 — How well-defined are the technical requirements and cost baseline?
5 / 5 — What is the procurement urgency?

Pricing Model Selection

Three fundamental pricing structures, each allocating risk differently between buyer and seller. Complements the contract type selection in the Digital Procurement tool.

Fixed Price (FFP)

Buyer pays an agreed price regardless of seller's actual cost
  • Maximum cost certainty for the buyer
  • Seller bears full cost-overrun risk
  • Requires stable, well-defined requirements
  • Incentivises seller efficiency — profits are kept
  • Standard for COTS, spares, commodity buys
  • Use with: Open competition / Framework / G-G FMS cases
Buyer Cost Risk
Seller Cost Risk

Cost Plus (CPFF / CPIF / CPAF)

Buyer reimburses actual allowable costs + negotiated fee
  • Buyer bears cost-overrun risk (bounded by ceiling price)
  • Appropriate for high technical risk / R&D programmes
  • Requires open book accounting from contractor
  • Fee variants: Fixed Fee | Incentive Fee | Award Fee
  • Typically used: satellites, EW, novel platforms, development
  • Use with: Closed competition / Direct / G-G development
Buyer Cost Risk
Seller Cost Risk

Target Cost (Fixed Price Incentive)

Agreed target + share formula for over/under-runs
  • Buyer and seller share cost risk via share ratio (e.g. 60/40)
  • Target cost, target profit, ceiling price all negotiated
  • Incentivises seller to manage costs below target
  • Best fit: naval vessels, complex systems, development-to-production
  • Requires open book during development; transitions to FFP at production
  • Use with: Closed competition / G-G development phases
Buyer Cost Risk
Seller Cost Risk

Pricing Model Selection Logic

Requirements
Stability?
High
→ Fixed Price
|
Medium
→ Target Cost
|
Low
→ Cost Plus
Key principle: Pricing model and purchase method are independent decisions. An open competition can use any pricing model; a G-G deal can be Fixed Price (FMS case) or Cost+ (development). Choose the pricing model on technical risk; choose the purchase method on market structure and policy.

Pricing Model Comparison by Equipment Type

Equipment Preferred Pricing Ceiling / Limit Open Book? Key Condition
Fighters / Combat Aircraft (production)Fixed PriceContracted priceNoStable spec, repeat production lot
Satellite (GEO, novel)Cost+ / Target CostCost ceiling in contractYesHigh technical risk, new technology
Satellite (repeat series)Fixed PriceContracted priceNoHeritage design, proven supply chain
Naval Vessel (lead ship)Target CostCeiling price agreedYesShare ratio negotiated; transition to FFP for batch
Missiles (production)Fixed PriceUnit priceNoProven design, volume ordering
EW / Classified R&DCost+ Fixed FeeEstimated cost + feeYesHigh technical uncertainty, exploratory
IT/Cyber ServicesFixed Price / T&MNTE ceilingPartialT&M only where scope undefined
Sustainment / MRO (framework)Fixed RatesRate cardOptionalVolume-dependent discounts; open book for benchmarking
UAS DevelopmentTarget Cost → FFPStage gatesYes (dev phase)Development Cost+ transitions to production FFP at maturity

Open Book Procurement

Open book procurement requires the contractor to provide transparent access to cost data, enabling independent verification and equitable negotiation. It is the foundation of any Cost+ or Target Cost contract.

Open Book Principles

COST TRANSPARENCY

Contractor provides full visibility of actual incurred costs: labour, materials, sub-contractors, overheads, profit.

INDEPENDENT AUDIT

Buyer retains right to audit books via a Delegated Contracting Authority (DCA) or third-party Cost Assurance Analyst.

FEE NEGOTIATION

Fee (profit) is negotiated separately from cost. Fee structure (Fixed / Incentive / Award) drives contractor behaviour.

COST CONTROL

Enables buyer to challenge inefficiencies, reject unallowable costs, and implement Should-Cost benchmarks.

Interactive Open Book Cost Calculator

Model a Cost+ Fixed Fee contract. Adjust the cost elements and fee rate to see the negotiated contract value.

Direct Cost Inputs (£K)


Overhead & Fee Parameters

Contract Value Breakdown (£K)

Open book note: In a genuine open book contract, all cost lines above must be evidenced by the contractor's accounts. The buyer may challenge overhead rates using market benchmarks or should-cost analysis.

Open Book vs Closed Book — When to Use Each

CriterionOpen BookClosed Book (FFP)
Technical maturityLow–Medium (TRL 1–6)High (TRL 7+, production)
Cost visibilityFull access; audit rightsNo access after award
Contractor efficiency incentiveModerate (fee-driven)High (profit from underrun)
Buyer cost riskHigher (pays actual cost)Low (fixed obligation)
Suitable purchase methodDirect / Closed Competition / G-G devAny — open / framework / G-G FMS
Admin burdenHigh — requires cost assurance resourceLow — invoice and close
Typical useDevelopment, novel platforms, EW, space devProduction, COTS, repeat buys, spares

Midlife Upgrades & Life Extension

Midlife upgrades represent a structurally distinct procurement event. The platform is a sunk cost; the upgrade must be procured as a new capability with its own method, pricing model, and risk allocation strategy.

Platform Lifecycle — Procurement Events

Phase 1
Initial Procurement
Primary method applies
All Methods
Phase 2
Operational Service
Framework sustainment
Framework / Direct OEM
Phase 3 ★
Midlife Upgrade (MLU)
New procurement event
Method decision required
Phase 4
Life Extension (LEP)
Structural / system refresh
Direct OEM or Competition
Phase 5
End of Life / Disposal
Support wind-down
Framework / Direct

MLU Procurement Complexity Factors

Factors Favouring Direct / G-G

  • Original OEM holds IP on aircraft/system integration
  • Export controls (ITAR) restrict upgrade component supply
  • Fleet-wide configuration control requires OEM involvement
  • Safety/airworthiness authority mandates OEM certification
  • Allied interoperability or software baseline synchronisation

Factors Enabling Competition

  • Upgrade is a modular, open-architecture sub-system
  • Interface control documents (ICDs) are government-owned
  • Multiple suppliers can meet qualification requirements
  • Government holds design authority for the platform
  • Non-recurring engineering (NRE) has already been funded

Interactive MLU Advisor

Select the upgrade type and platform context to receive tailored purchase method advice.

Pricing Models for MLU Phases

MLU Phase Recommended Pricing Open Book? Notes
Feasibility Study / Concept Phase Cost+ Fixed Fee Yes Scope undefined; time-boxed; output is feasibility report + ICD
Preliminary Design (PDR) Cost+ / Target Cost Yes Technical risk still high; milestone payment structure
Critical Design & Integration (CDR) Target Cost Yes Share ratio incentivises cost discipline; ceiling price mandatory
Qualification & Test (FSED) Target Cost → FFP Partial Transition to FFP once design is proven
Production Installation (fleet-wide) Fixed Price No Design stable; learning curve and volume discounts negotiated
Post-Installation Support / ILS Fixed Rates (Framework) Optional Rate cards agreed; open book used for benchmarking only

Full Decision Matrix

Consolidated view across all purchase methods and pricing models to support senior procurement decision-making. Use alongside the contract type decision from the companion Digital Procurement tool.

Method × Pricing Model Compatibility Matrix

Hover any cell for rationale. ✓ Best = natural combination · Possible = with justification · = policy/audit issues

Purchase Method ↓ / Pricing → Fixed Price (FFP) Target Cost (FPIF) Cost+ (CPFF/CPIF) Open Book + T&M FMS / G-G Case
G-G (Government-to-Government) ✓ FMS production lots Possible (co-dev) Possible (dev phase) Rare ✓ Standard FMS case
Framework Contract ✓ Primary method Not typical Not recommended Possible (services) N/A
Direct (Single Source) Possible (production) ✓ Complex direct awards ✓ Primary for R&D/dev ✓ Cost assurance reqd N/A
Closed Competition Common (system devel) ✓ Lead platform dev ✓ R&D, novel systems With cost assurance N/A
Open Competition ✓ Default for production Less common Rarely appropriate Difficult to audit widely N/A
✓ Best Natural combination
Possible With justification
Not recommended Policy / audit issues

Equipment Type → Full Procurement Strategy

Equipment Method Pricing Model Open Book MLU Method MLU Pricing
Combat Aircraft (production) G-G / Closed Fixed Price No Direct OEM Cost+ → FFP
GEO Satellite (novel) Closed Competition Cost+ / Target Yes Direct OEM Cost+
Naval Vessel (lead ship) Closed Competition Target Cost Yes Direct OEM / Closed Target Cost
Missile / Munition (production) G-G / Closed Fixed Price No G-G / Direct Fixed Price
Armoured Vehicle Open Competition Fixed Price No Closed / Direct Target Cost
Radar / EW System Closed Competition Cost+ / FFP Dev phase Direct OEM Cost+
Ground Station / Comms Open Competition Fixed Price No Open / Framework Fixed Price
IT / Cyber Systems Framework / Open Fixed Price / T&M Partial Framework Fixed Rates
Sustainment / MRO Framework Fixed Rates Optional N/A N/A
R&D / Demonstrator Closed / Direct Cost+ Fixed Fee Yes — mandatory N/A (not production) N/A
UAS / Drone (system dev) Open / Closed Cost+ → FFP Dev phase Open Competition Fixed Price

Procurement Risk Register — Method Selection

RiskTriggered ByPurchase Method MitigationSeverity
Cost overrun — no ceiling Cost+ without ceiling price clause Mandate cost ceiling / NTE; insert should-cost benchmarks High
Single-source lock-in Direct contract, no competition Government IP ownership; dual-source strategy; competitive re-compete at MLU High
G-G dependency / policy risk G-G for core capability Ensure national maintenance rights; escrow source code; ILS local content Medium
Framework under-utilisation Poorly scoped framework Define realistic call-off volumes; minimum order obligations; regular benchmarking Medium
Open competition: no qualified bidders Market smaller than assumed Pre-RFP market engagement; pre-qualification; fallback to closed competition Medium
MLU IP dispute OEM owns integration IP Negotiate IP rights at initial contract; Government Purpose Rights clause High
Open book audit failure Contractor non-compliance Audit rights in contract; step-in rights; withheld progress payments Medium

Procurement Routes — Full Taxonomy & Spend Data

The five routes in this tool are the primary competitive posture decisions. A complete procurement strategy also requires selection from the broader route taxonomy below, which governs legal authority, vehicle type, and international mechanism.

Source note: Spend breakdowns are drawn from UK MOD Trade, Industry and Contracts 2024/25 (published Sep 2025, GOV.UK); MOD Trade, Industry and Contracts 2023/24 (published Mar 2025); and UK Commons Library Briefing CBP-9566 (Mar 2025). US figures reference DoD/FAR/OTA statutory authorities. Percentages reflect expenditure by value, not contract count. Equipment-tier estimates are professional judgements consistent with published data — no single government source disaggregates spend by strategic/operational/tactical/consumable tier.

Complete Procurement Route Taxonomy

Eight route families, each with distinct legal basis, oversight regime, and typical use case. The five primary methods in this tool sit within the Competition Posture column.

Route Family Legal Basis (UK/EU) Legal Basis (US) Competition Posture Open Book? Typical Use
Government-to-Government (G-G) Exempt: Procurement Act 2023; bilateral MOU/DCA Arms Export Control Act; FAR 6.302-4 None No (FMS pricing opaque) Allied military platforms, ITAR-controlled systems, FMS, OCCAR, NATO agency
Framework Agreement / IDIQ Procurement Act 2023 s.45; PCR 2015 Reg 33 FAR Subpart 16.5 (IDIQ); GSA Schedules Pre-competed Optional at renewal Sustainment, IT, professional services, spares; multi-year recurring spend
Direct / Single Source Procurement Act 2023 s.41; SSCR 2014 (regulated profit) FAR 6.302-1 to 6.302-7 (J&A required) None Mandatory (SSCR/TINA) OEM exclusivity, UOR, follow-on production, IP-locked capabilities
Closed / Restricted Competition Procurement Act 2023 s.19 (limited conditions); DSPCR Reg 26 FAR Part 15 (negotiated); DFARS 215.3 Restricted Recommended (Cost+) Classified programmes, small industrial base, space/EW systems
Open Competition Procurement Act 2023 s.14; above-threshold mandatory FAR Part 6 (CICA); SAP below threshold Full No (FFP standard) COTS, vehicles, IT, training systems, professional services, commodities
Other Transaction Authority (OTA)
US only — no direct UK equivalent
N/A (no UK OTA equivalent; DASA innovation grants partial analogue) 10 USC §4021–4022; not governed by FAR/CICA Flexible Negotiable Prototype/R&D with nontraditional contractors; production follow-on without FAR
Commercial Solutions Opening (CSO)
US DoD / expanding
DASA grants; Innovate UK Defence; competition notice 10 USC §3458; NDAA FY26 s.1823 expanded Open (commercial) No Commercial technology; AI/autonomous systems; VC-backed defence tech startups
Collaborative / Multinational Programme OCCAR Convention; NATO NSPA; bilateral MOU Foreign Comparative Testing; NSPA Consortium Partial (OCCAR audit) TYPHOON, NH-90, BOXER, FREMM, Meteor, MGCS; burden sharing and work-share
Private Finance Initiative (PFI) / DBFO
No new PFI in UK since 2018
Treasury Green Book; HMT PFI guidance (historic) Public-Private Partnership legislation Competitive tender Full (unitary charge model) Infrastructure: bases, accommodation, training facilities; asset off-balance sheet

Equipment Tier × Procurement Route — Estimated Spend Distribution

Interactive chart. Click a tier row to expand detail. Bars show estimated % of spend through each route family. Estimates are professional judgements grounded in UK MOD 2023/24 published data and NATO procurement literature — no single official source provides this exact disaggregation.

Tier definitions used:  Strategic = major platforms & programmes (unit cost >£500M, lifecycle >20yr) · Operational = system-level equipment (£10M–£500M) · Tactical = sub-system & individual equipment (<£10M unit) · Consumables = ammunition, fuel, spares, expendables

Sources & Methodological Notes

SourcePublisherDateUsed For
MOD Trade, Industry and Contracts 2024/25UK MOD / GOV.UKSep 2025Overall competitive/non-competitive split; FMS spend; framework spend
MOD Trade, Industry and Contracts 2023/24UK MOD / GOV.UKMar 202544% non-competitive, 37% competitive baseline figure; top-10 supplier concentration
Annual Qualifying Defence Contract Statistics 2023/24SSRO / GOV.UKJul 2024Single-source contract volume (59 QDCs/QSCs); average profit rate 9.47%; avg duration 4.9yr
Defence Procurement Reform (CBP-9566)UK Commons LibraryMar 2025Historical competitive split; SSCR framework; Procurement Act 2023 route structure
UK Public Sector Defence Procurement TrackerTussell2024/25Framework agreement usage (£5bn, 10 frameworks in 2024); SME participation (5%)
EO 14265: Navigating Defence Procurement ReformsTroutman Pepper / DoDMay 2025AAF six acquisition pathways; OTA statutory basis 10 USC §4021-4022
FY26 NDAA — Key ProvisionsRyan & Wetmore / CongressMar 2026CSO expansion (s.1823); CAS threshold changes; nontraditional contractor provisions
GAO Report: Reciprocal Defence Procurement AgreementsUS GAO2024RDP agreement framework; 28 partner countries; $9.7bn annual US defence exports
FAR / DFARS / 10 USCUS Federal Acquisition RegulationCurrentUS contract type authorities; competition requirements; OTA statutory basis
Professional judgement (LASS TECH)2025Equipment-tier × route distribution estimates; no single official source provides this breakdown

Contract Type Subtypes — Defined

The pricing model labels CPFF, CPIF, CPAF, FFP, FPIF, T&M, and IDIQ each describe a specific legal and financial structure with distinct risk allocation, fee mechanics, and compliance requirements. Select any card for full definition.

Where does Open Book fit? Open book is not a contract type — it is an accounting access regime applied on top of a contract type. It is mandatory under the UK Single Source Contract Regulations (SSCR 2014) for qualifying direct awards, and standard practice in Cost+ and Target Cost contracts globally. It does not make sense to use Open Book with FFP post-award because the price is already fixed; it may be used pre-award on FFP to validate a should-cost estimate. This tab clarifies where each contract type requires, recommends, or excludes Open Book access.

Contract Type Comparison — Quick Reference

TypeFee StructureCost Risk: BuyerCost Risk: SellerOpen Book?Typical UseFAR Ref

Open Book — When It Applies

ScenarioOpen Book?Why / Why NotUK Regime
FFP — post-award No Price is fixed; cost visibility has no effect on buyer's obligation. Auditing actual costs post-award provides no financial benefit. Not required. May be used for benchmarking at recompete.
FFP — pre-award (should-cost) Optional Buyer may require cost breakdown to validate proposed price before agreeing a fixed price. This is "open book to award" not "open book contract". TINA (Truth in Negotiations) equivalent: required above threshold for non-competitive awards.
FPIF / Target Cost Recommended Share ratio only works fairly if actual costs are verifiable. Without cost visibility, buyer cannot confirm whether underrun was efficiency or underreporting. SSCR 2014 profit rate step process requires cost transparency.
CPFF / CPIF / CPAF Mandatory Buyer reimburses actual costs — cost visibility is the entire mechanism. Without it, buyer has no ability to challenge unallowable or excessive costs. SSCR 2014 mandatory for QDCs; DCAA audit rights in US Cost+ contracts.
T&M (Time & Materials) Mandatory Labour rates and material costs must be auditable. NTE (not-to-exceed) ceiling requires cost tracking. Required; T&M is highest-risk contract type for buyer and requires active cost surveillance.
Framework (call-off) At renewal Post-award call-off prices are pre-agreed. Open book used at framework renewal to benchmark rates against market and challenge overhead creep. SSCR applies if individual call-off becomes a QDC (>£5M, non-competitive).
G-G / FMS No (FMS) FMS pricing uses US Government audited standard rates; UK buyer has no access to US contractor cost books. DCS (Direct Commercial Sales) can include open book. FMS exempt from SSCR; DCS treated as direct contract.
Bottom line: Open Book is essential for Cost+ and T&M contracts, recommended for Target Cost/FPIF, optional pre-award for FFP validation, and irrelevant post-award on FFP. It is not a procurement route or contract type — it is an access right written into the contract conditions. The SSCR 2014 (UK) and TINA/DCAA regime (US) are the statutory frameworks that mandate it where applicable.