A supplier cannot perform an obligation when the customer withholds the conditions required to perform it.
The Week 5 materials address this through tender of performance and prevention of performance. Where one party validly offers performance and the other refuses it, the performing party may be discharged from further obligations. Where performance requires cooperation and that cooperation is withheld, the performing party may have a claim for work or expense already incurred.
This is one of the clearest systems lessons in the Week 5 material.
The Strategic Context
Most complex contracts require reciprocal action.
A contractor needs site access. A technology supplier needs data and decisions. A designer needs approved requirements. A manufacturer needs final specifications. A commissioning team needs utilities and operating permits.
Contract performance is therefore not simply “supplier responsibility”. It is an interface system.
The Week 5 source uses refusal of site access as a direct example of prevention and De Barnardy v Harding to illustrate a party withdrawing authority after the other party had already incurred expenditure.
What Leaders Commonly Misread
The first mistake is demanding supplier performance while failing to meet client dependencies.
The second is assuming access, information and approvals are administrative matters rather than contractual inputs.
The third is treating a refused tender of performance as ordinary delay. If the supplier offered compliant performance and the customer refused it, the allocation of responsibility may change.
The fourth is failing to record causation. When a project is delayed, both parties may later argue that the other caused it.
Current Australian prevention principles and interaction with contractual extension-of-time mechanisms should be independently verified. [FACT CHECK REQUIRED]
Reframing the Issue
Performance should be modelled as a dependency network.
For every critical supplier obligation, ask:
What must the customer, owner, program or another contractor do first?
If that dependency is not visible, the project can create breach through its own inaction.
Strategic Analysis: Client Obligations Can Be Critical Path
Hypothetical infrastructure example: A contractor is scheduled to install equipment on 1 July. The owner must provide access, isolation and an approved lift plan. The contractor mobilises but access is refused because internal permits are incomplete.
From an operational perspective, installation did not occur.
From a governance perspective, the more important question is why.
If the owner prevented performance, it should not manage the event as though the contractor simply failed to deliver.
The Week 5 tender concept also matters where a supplier makes a compliant offer of performance inside the contractual window and the buyer rejects it for reasons not supported by the contract.
Decision Framework
For every critical milestone, identify:
Supplier obligation
What must the supplier deliver?
Client dependency
What must the customer provide first?
Timing
When must that input be available?
Evidence
How will readiness and tender of performance be recorded?
Consequence
What happens if cooperation is withheld?
Recovery
What cost or schedule consequence may result?
This should be integrated with project planning.
From Strategy to Execution
Immediate action: add client obligations to the master schedule and risk register.
Medium-term capability building: create formal readiness gates for access, data, approvals and interfaces before supplier mobilisation.
Long-term strategic positioning: measure owner-caused delay across the portfolio. Supplier performance cannot be improved if the organisation does not understand its own contribution to failure.
Interface Governance
Prevention disputes often reveal weak interface ownership. One team may believe access is a facilities issue, another may treat permits as a safety issue, while the contractor assumes the project manager owns both. When responsibilities are fragmented, supplier delay can be created by the customer's internal organisation.
A stronger program model assigns an accountable owner to every external dependency and measures readiness before mobilisation. The purpose is not to shift blame internally. It is to ensure that the system required for performance exists before the organisation demands performance from others.
Governance Test
Before a supplier is declared late, the project should confirm that every client-side prerequisite due before that milestone was actually available. This should include access, approvals, information, interfaces and any customer-furnished resources. Recording that evidence creates a fairer performance assessment and improves the quality of any later delay claim. It also helps leadership identify whether the real constraint sits with the supplier or inside the organisation itself.
Signals to Monitor
Watch for contractors arriving to inaccessible sites, late design approvals, repeated “waiting for client information” status, rejected deliveries with unclear contractual basis, and projects recording supplier delay without identifying customer-caused constraints.
Questions for the Leadership Team
- Which client obligations sit on the critical path?
- Are they visible in the same schedule as supplier work?
- How is tendered performance evidenced?
- What happens when the customer prevents access or approval?
- Are supplier scorecards adjusted for owner-caused delay?
- Which recurring internal bottlenecks are creating external claims?
Closing Perspective
Performance is a two-party system.
A contract that demands delivery without governing the inputs necessary for delivery does not create accountability. It creates argument.
Related article: The Contract You Did Not Write: How Implied Terms Enter Commercial Relationships
Related article: Contract Management Is More Than Contract Administration
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