The Procurement Model
Decision You're Rushing

Most capital works projects we see have already picked a procurement model before anyone has properly asked whether it fits the project. It's usually whatever was used last time, whatever the panel of pre-qualified contractors supports, or whatever the internal template defaults to. The decision that will shape cost certainty, program risk and dispute exposure for the next one to three years gets made in about ten minutes, early in a business case, by whoever happened to be in the room.

That's a mistake worth fixing, and it's fixable. Procurement model selection is not a legal formality or a probity exercise — it's a risk allocation decision. Get it wrong and you don't just get a worse commercial outcome, you get a fundamentally different project than the one you thought you were running.

Why this decision matters more than it looks

Every procurement model is, underneath the paperwork, an answer to one question: who carries the risk of the unknown? Design risk, latent site conditions, interface risk between packages, program risk, market pricing risk — all of it has to sit somewhere. The procurement model you choose determines who's holding it, and whether they're the party best placed to manage it.

Owners who don't interrogate this properly tend to make the same error in both directions. Either they push too much risk onto a contractor who prices it in heavily (or worse, prices it optimistically and claims it back later), or they retain risk themselves without the internal capability to actually manage it — which is its own kind of expensive.

The models, and what they actually mean for you

Traditional (design-bid-build)

You commission the design, then tender the construction against a completed or near-complete design. This gives you the most cost certainty at tender stage and the clearest scope definition — provided the design is genuinely finished. The risk is almost entirely a design-quality risk: if the design has gaps, the contractor's variation claims will find them, and you'll pay for the gap plus a margin, plus program impact, plus the friction of a dispute about whose fault it was.

Design and construct (D&C)

Single point of responsibility, contractor carries design risk, and you get earlier price certainty against a performance specification rather than a completed design. Works well when your requirements are genuinely fixed and well defined. Works badly when the owner keeps changing their mind during design development, because every change is now a variation against a contractor-controlled design, not a design refinement you control.

Early contractor involvement (ECI) / managing contractor

The contractor is engaged during design development to bring constructability and programming input before scope is locked. This is the model that best suits brownfield and live operational environments — exactly the kind of work where the biggest risks are things a designer sitting at a desk cannot see. The tradeoff is you lose competitive tension on price until the construction phase is negotiated, so your probity and governance framework needs to be built for that from the outset, not retrofitted when someone asks why there wasn't a second quote.

Construct only

You retain full design control and only procure the build. This only works if you have genuine in-house capability to manage design coordination and constructability review yourself — otherwise you've just relocated the risk that D&C would have transferred, without gaining anything for it.

Where councils and asset owners most commonly get it wrong

• Choosing D&C for a live operational environment with an incomplete interface definition. The contractor prices the interface risk conservatively, or worse, doesn't understand it well enough to price it at all — and you find out during construction.
• Choosing traditional procurement with a design that's "80% done." The last 20% is disproportionately where the risk lives. Tendering against it just moves the argument about who owns that 20% into the construction phase, where it costs more to resolve.
• Assuming ECI means no cost control. A well-run ECI process has target cost mechanisms, open-book reporting and clear gate criteria before you commit to the construction phase. Owners who don't set this up properly end up with neither the collaboration benefits nor the cost certainty.
• Letting probity concerns drive the model rather than inform it. Probity is a real constraint, particularly for councils and water utilities, but it should shape how you run ECI or negotiated procurement — not rule it out by default in situations where it's genuinely the better fit.

What to do before you go to market

Before locking in a procurement model, be honest about three things: how complete and reliable is your design and site information really, how much genuine capability do you have in-house to manage the risk you're proposing to retain, and how live or constrained is the environment the work sits in. Those three answers, tested against each other, will point you toward the right model far more reliably than habit or template will.

This assessment takes a few days properly done. It's worth doing before the business case locks in a model that the rest of the project then has to live with for its entire duration.