In construction, the Guaranteed Maximum Price (GMP) is often seen as the point where everything becomes clear. 

The number is set. The budget feels defined. The project moves forward with confidence. 

But in reality, a GMP doesn’t create clarity on its own, it reflects it. And when that clarity isn’t fully there, the GMP can introduce uncertainty instead of reducing it. 

We view the GMP not as a finish line, but as a critical moment to align scope, assumptions, and expectations across the entire team. 

A GMP is only as strong as what’s behind it

A GMP isn’t just a number, it’s a snapshot in time. 

Its reliability depends on a few key things: 

  • How complete the design is  
  • How clearly the scope is defined  
  • How well assumptions are understood  
  • Solid understanding of current market conditions 

When those pieces aren’t fully aligned, the GMP becomes open to interpretation, and that’s where issues begin. 

Where things can get off track 

Most GMP challenges don’t come from bad intent; they come from gaps in clarity. 

Here’s where we typically see breakdowns: 

Assumptions that aren’t fully shared
When assumptions live in spreadsheets instead of conversations, misalignment is almost guaranteed. 

Too many allowances
Allowances can help early on, but too many push decisions down the road and bring uncertainty with them. 

Limited trade partner input
Without real-time feedback from trade partners, GMPs can miss current market conditions and constructability insights. 

Scope that leaves room for interpretation
If scope isn’t clearly defined, different teams will define it differently, and that leads to change. 

A better approach: clarity from the start 

A stronger GMP isn’t built by adding more contingency, it’s built by removing uncertainty. 

Our Project Planning Group (PPG) leads an approach grounded in transparency and alignment. Simply put: we are not just cost reporters, we are cost strategists. 

That means: 

  • Every assumption is defined and discussed
    Nothing hidden, nothing implied.  
  • Allowances are minimized wherever possible
    We push for decisions early to reduce risk later.  
  • In-house quantity take-offs on all trades
    Verify subcontractors have accurate proposals 
  • Trade partners are engaged early
    Bringing real-world pricing and expertise into the process

  • Scope is clearly aligned across the team
    Everyone is working from the same understanding.

From a number to a tool

When done right, a GMP becomes more than a budget, it becomes a tool for decision-making. 

It helps teams: 

  • Understand and mitigate risk early  
  • Make informed choices during design  
  • Reduce surprises during construction  

This is especially important in complex, occupied, and historic environments, where unknowns are part of the process, and clarity matters even more. 

The Christman difference 

On projects like the Cannon House Office Building, we’ve seen firsthand how early alignment and transparent GMP development lead to better outcomes. 

Our focus is simple: define what others leave undefined. 

Because when teams are aligned before construction begins, projects don’t just stay on budget, they run smoother from start to finish. 

A GMP should do more than set a limit, it should create understanding. 

Because when everyone knows what’s behind the number, there’s less guesswork, fewer surprises, and a clearer path forward.