Construction delivery methods

Why Delivery Method Matters

The project delivery method defines the contractual relationships between owner, designer, and contractor, and that determines who bears which risks, when prices are locked, and how design and construction overlap. Choice of delivery method has a larger effect on outcomes than most design choices.

Design-Bid-Build (DBB)

The traditional method. The owner contracts separately with the designer and the contractor. Design is completed before the project is bid. Contractor is selected by lump-sum competitive bid.

• Pros: clear scope at bid, competitive pricing, low owner involvement during construction
• Cons: no contractor input during design, longest overall schedule, adversarial change-order culture
• Best for: well-defined scope, public projects with bid requirements, simple buildings

Construction Manager at Risk (CMAR)

The owner hires the designer and separately hires a Construction Manager (CM) early in design. The CM provides preconstruction services, then converts to a Guaranteed Maximum Price (GMP) at some point in design, taking on construction risk.

• Pros: contractor input during design, faster overall schedule (overlap), cost certainty at GMP
• Cons: GMP often set before drawings are complete, design-construction interface gaps still exist
• Best for: complex commercial buildings, owners willing to invest in preconstruction

Design-Build (DB)

A single entity holds responsibility for both design and construction. The owner contracts with a design-builder, who in turn engages designers and trades.

• Pros: single point of responsibility, fastest delivery, fewer design-construction conflicts
• Cons: owner has less direct control over design, scope changes can be expensive
• Best for: schedule-driven projects, owners that can define performance criteria clearly

Progressive Design-Build (PDB)

A two-phase design-build approach. Phase 1 is design and preconstruction services on a professional-services basis. Phase 2 converts to a fixed-price or GMP contract for construction. Increasingly common on large public projects.

• Pros: collaborative early design, owner retains design influence, price certainty at Phase 2
• Cons: more complex contracting, owner may pay for design even if Phase 2 doesn't proceed
• Best for: complex public infrastructure, large institutional projects

Integrated Project Delivery (IPD)

A multi-party contract among the owner, designer, contractor, and key trade partners. Risks and rewards are shared based on collective project outcomes. Common in healthcare and complex institutional work.

• Pros: aligned incentives, intensive coordination, fewer claims
• Cons: contract complexity, requires sophisticated owner, limited contractor pool
• Best for: highly complex projects, owners with prior IPD experience

Public-Private Partnership (P3 / DBFOM)

A private consortium designs, builds, finances, operates, and maintains a public facility over decades in exchange for availability payments or user fees. Most common on transportation infrastructure but increasingly used for social infrastructure.

• Pros: private capital, lifecycle accountability, performance-based incentives
• Cons: very high transaction costs, complex contracts, long-tail risks
• Best for: large infrastructure with long operating life and reliable revenue

How Delivery Method Affects Drawing Quality