17.2 Committed Costs, Accruals, Work-in-Place & Invoice Validation
Key Takeaways
- Project cost passes through four distinct states — estimated, committed, incurred/accrued, and actual (invoiced) — and blueprint tasks 1.R, 1.S, 1.T, and 1.U examine the transitions between them.
- Earned value requires actual cost to be recorded in the same period as the earned value it matches, which means accruals must be raised for work performed but not yet invoiced.
- A commitment-based forecast decomposes as actuals to date plus open commitments plus estimate to complete on uncommitted scope, confining forecast uncertainty to the last term.
- Work-in-place validation tests whether independently measured physical progress supports the accrued value; the classic error is accruing installed quantities and their embedded materials twice.
- Invoice validation extends the three-way match with progress, retention, tax, and back-charge checks, and must reverse the corresponding accrual — unreversed accruals systematically overstate actual cost and collapse CPI without cause.
17.2 Committed Costs, Accruals, Work-in-Place & Invoice Validation
Four consecutive blueprint tasks — 1.R track actual and accrued costs, 1.S track committed costs, 1.T validate invoices, and 1.U validate work-in-place accruals — describe the monthly mechanics of cost control. They sit inside the 36% domain and they are the tasks that separate a cost engineer from an estimator. Candidates who prepare only estimating and EVM formulas lose points here, because these questions are about when a cost becomes real and which number belongs in which report.
1. The Four Cost States
A dollar of project cost passes through recognisable states. Confusing them is the single most common cost-reporting error.
| State | Definition | Trigger | Where it shows up |
|---|---|---|---|
| Estimated | Predicted cost of scope not yet placed | Estimate approval | Estimate, budget, forecast |
| Committed | Legally obligated by a purchase order, subcontract, or contract change | PO or contract award | Commitment register, cash flow forecast |
| Incurred / accrued | Work physically performed or goods received, not yet invoiced or paid | Physical progress or receipt | Accrual journal, actual cost (AC) for EVM |
| Actual (invoiced/paid) | Approved invoice recorded, and ultimately paid | Invoice approval / payment | General ledger, cash flow actuals |
[!IMPORTANT] Earned value uses cost incurred, not cash paid. A project that ignores accruals and reports only paid invoices will show an artificially high CPI early — value has been earned, but the matching cost has not been recorded yet. The correction, when the invoices land, looks like a sudden cost blowout that is really just an accounting catch-up. Under EVM discipline, actual cost (AC) must be recorded in the same period as the earned value (EV) it corresponds to.
2. Committed Cost (Task 1.S)
A commitment is a legal obligation to pay. It is created at award, not at invoice, and it is the earliest reliable signal of where the project's money is going.
Committed cost management formula:
Total forecast = Actuals to date + Open commitments + Estimate to complete on uncommitted scope
That decomposition is the backbone of a commitment-based forecast. Its power is that the middle term is known with contractual certainty, so forecast uncertainty is confined to the third term. On a project that is 70% committed, only 30% of remaining spend is genuinely uncertain — a much stronger position than a CPI-based forecast alone would suggest.
Practical rules:
- Track commitments gross and net. Gross commitment is the award value; net open commitment is award value less amounts already invoiced. Reports that mix the two double-count.
- Change orders create commitment. An approved contract change increases the commitment even before any work is performed against it (blueprint task 1.J, "confirm change orders are included in baseline").
- Contingency is not a commitment. Unallocated contingency stays outside the commitment register until it is drawn down into a specific scope.
3. Accruals and Work-in-Place Validation (Tasks 1.R and 1.U)
An accrual records cost for work performed or goods received in a period when the invoice has not yet arrived. Work-in-place (WIP) is the physical measure that justifies the accrual.
The validation question is always the same: does the claimed physical progress support the accrued value?
| Accrual basis | How to validate | Failure mode |
|---|---|---|
| Quantity installed | Field survey or quantity-surveyor measurement against the takeoff | Double-counting material delivered but not installed |
| Milestone achieved | Objective completion evidence, signed off | Milestone claimed on substantially incomplete work |
| Percentage complete | Independent physical assessment, not contractor self-report | Optimistic self-assessment inflating cost and EV together |
| Goods receipt | Receiving report matched to PO line | Materials accrued at site but still owned by the vendor |
Worked accrual validation
A subcontractor claims $1,400,000 of concrete placement for the month. Records show:
- Contract unit rate: $280 per m3
- Quantity surveyor's independent measure: 4,300 m3 placed this period
- Materials delivered to laydown but not placed: 600 m3 of reinforcing steel, separately supplied
Supportable accrual = 4,300 m3 x $280 = $1,204,000. The $196,000 difference is not payable this period: it reflects quantity claimed but not measured as in place. The delivered rebar is a separate materials commitment, receipted against the supply PO — it does not belong in the concrete placement accrual at all.
[!WARNING] The classic double count. Accruing installed quantities and separately accruing the materials embedded in those quantities books the same cost twice. Every accrual review should ask which line items could contain the same physical scope.
4. Invoice Validation (Task 1.T)
Invoice validation is a control, not a clerical step. The standard test is the three-way match, extended for construction:
- Invoice to purchase order or contract — is the rate the contracted rate, and is the scope within the contract?
- Invoice to receipt or measurement — did the quantity actually arrive or get installed?
- Invoice to progress record — is claimed progress consistent with the independent measure?
- Commercial terms — retention withheld at the contracted percentage, correct tax treatment, escalation applied only where the contract allows it, back-charges deducted.
- Reversal of prior accrual — when the invoice is booked, the corresponding accrual must be reversed.
[!IMPORTANT] Step 5 is where cost systems break. If accruals are raised but never reversed when the invoice arrives, actual cost is systematically overstated, CPI collapses without cause, and the EAC forecast becomes indefensible. Every period-end review should reconcile accruals raised, accruals reversed, and invoices booked.
A subcontractor submits a monthly claim of $1,400,000 for concrete placement at a contract rate of $280 per cubic metre. The project's quantity surveyor independently measures 4,300 m3 placed during the period. Separately, 600 m3 worth of reinforcing steel has been delivered to the laydown yard under a different supply purchase order but not yet installed. What accrual should be recorded against the concrete placement account?
A project is reporting a cumulative CPI of 1.18 at month four. On review, the cost engineer finds that the project books actual cost only when supplier invoices are approved for payment, and raises no accruals. Two subcontractors work on 60-day invoicing cycles. What is the most likely explanation, and what is the correct remedy?
A project is 70% committed by value. Actual costs to date are $42,000,000, open commitments are $63,000,000, and the estimate to complete on scope that has not yet been committed is $18,000,000. Why is this decomposition often more defensible than a CPI-based forecast alone?