What is should-cost modeling for defense bids?

Should-cost modeling for defense bids is a disciplined, evidence-based estimate of what a program, product, subsystem, or service should cost your company or a key supplier to perform, given the actual technical scope, quantities, schedule, manufacturing approach, labor content, material inputs, indirect rates, and compliance obligations. In aerospace and defense, it helps leadership build a credible cost volume, challenge supplier pricing, test whether a proposal is executable at the proposed margin, and decide whether to pursue, re-scope, or walk away from an opportunity.

For executives, the value is not the spreadsheet by itself. The value is turning a request for proposal into a fact-based operating view: what really drives cost, which assumptions are fragile, where negotiation headroom exists, and whether the business can meet a price-to-win objective without relying on unrealistic labor, supplier concessions, or schedule recovery after award.

What the term means

A should-cost model is a bottom-up, driver-based view of achievable cost. Instead of anchoring on last price paid or on a top-down target, it decomposes the bid into the resources required to deliver the contracted scope. In a defense setting, that usually means estimating recurring and nonrecurring costs for material, engineering, manufacturing, quality, supply chain, test, program management, and indirect expense, then tracing those elements back to specific technical and contractual assumptions.

It is important to separate should-cost from nearby terms. Price-to-win asks what price may be needed to win in a competitive field. A historical estimate extrapolates from prior work. And within Department of Defense acquisition, should-cost can also refer to management efforts to drive costs below a will-cost baseline. For bidders, the practical use is simpler: what should this work cost us, or a supplier, if the plan is realistic and execution is disciplined?

Why it matters in defense bidding

Defense proposals are unusually sensitive to estimating quality because the work is often low-volume, technically specific, heavily documented, and dependent on a concentrated supplier base. Small errors in hours, yield, lot sizing, special processing, or test assumptions can erase margin quickly, especially in fixed-price development, production, or sustainment work.

• Requirements are dense. Contract line item numbers (CLINs), Contract Data Requirements Lists (CDRLs), technical data, first article requirements, and configuration control create cost that is easy to miss if the team prices only the hardware.
• Supply chains are constrained. Sole-source components, long-lead materials, domestic sourcing requirements, and obsolescence can materially change the cost position.
• Government review can be detailed. Under FAR Part 15, negotiated procurements may involve price analysis, cost analysis, and close scrutiny of the basis of estimate.
• Execution risk sits with the contractor. If the proposal assumes faster learning, lower rework, or better supplier concessions than the operating model can deliver, the bid may win and still destroy value.

For some negotiated proposals, offerors may also need to support estimates with detailed proposal narratives and, where applicable, certified cost or pricing data. Even when that standard does not apply, management still needs an internal view that is more rigorous than a mark-up on last year’s bid. A well-built should-cost model gives leadership an internal truth before the external price is locked.

How should-cost modeling works

Translate the solicitation into a cost structure

The team first turns the request for proposal, statement of work, and technical package into a work breakdown structure (WBS). Each major work element receives a basis of estimate (BOE): quantity assumptions, labor content, material content, tooling, testing, inspection, and required documentation. Good teams explicitly separate recurring production cost from nonrecurring engineering, qualification, startup, and capital items so that the model reflects the real contract economics.

Build the cost stack from underlying drivers

The model usually includes direct material and subcontracts, direct labor hours by function or work center, learning curves, yields and scrap, special processes, quality assurance, tooling and test equipment, logistics and packaging, program management, and then indirects such as fringe, overhead, and general and administrative expense. For service-heavy bids, the same logic applies but the emphasis shifts toward labor mix, productivity assumptions, travel, software tools, transition effort, and subcontractor management. The point is not complexity for its own sake; it is traceability from scope to resource consumption.

Stress-test the estimate before it becomes a bid

A serious should-cost model is challenged against historical actuals, supplier quotes, capacity limits, learning already achieved on similar work, and likely schedule scenarios. Sensitivity analysis matters. If two assumptions drive most of the margin, management should know that before final pricing. The output is not only a number. It is a set of decisions: where to negotiate, what to redesign, whether to make or buy, where to seek scope clarification, and how far the final price can move before execution becomes unacceptable.

When the solicitation requires a detailed cost volume, the should-cost model often becomes the analytic backbone for the BOE narrative and management reviews. When the contract is competitive and evaluated more on total price, it is still valuable because it shows whether a lower price is operationally believable.

Practical example

Consider a contractor bidding a low-rate production lot for a line-replaceable unit. A key supplier submits a quote that appears consistent with prior pricing, so the capture team is tempted to accept it. The should-cost model breaks the quote into raw material, machining time, special processing, inspection, environmental stress screening, and recurring test labor, then adjusts for the new lot size and learning already achieved on the previous build.

The analysis shows that the supplier is pricing setup and inspection as if each unit were effectively a first article, and it is carrying scrap assumptions that no longer match current process yield. Management does not blindly cut the bid price. It uses the model to negotiate the supplier position, evaluate a second source, and decide how much savings must be contractually secured before the company relies on them in the proposal.

Benefits

• Better bid discipline: management sees whether the proposed price is supported by a realistic operating plan.
• Stronger supplier negotiations: the team can challenge quotes with fact-based assumptions rather than generic cost pressure.
• Improved margin protection: cost drivers are visible before award, when they can still be changed.
• Higher-quality proposal support: the cost volume and BOE are easier to defend when the estimate is traceable.
• Better post-award execution: the model can become the starting point for cost control, not just a proposal artifact.

Risks, limitations, and common misconceptions

• It is not the same as price-to-win. A technically sound should-cost view may still be above the market-clearing price.
• It can create false precision. If engineering maturity is low or requirements are unstable, too many decimal places can hide real uncertainty.
• Compliance costs are easy to understate. Documentation, configuration management, cybersecurity obligations when in scope, export controls, and quality requirements can be materially expensive.
• Supplier savings are not real until secured. Many proposals assume concessions that procurement has not yet negotiated.
• Historical data can mislead. Prior actuals are useful only if they are normalized for quantity, design changes, schedule, and learning.
• A model that dies at submission misses much of the value. The best organizations compare bid assumptions with actual performance and update future models accordingly.

How executives should think about it

Executives should treat should-cost modeling as a management capability that connects capture, engineering, supply chain, operations, finance, and proposal teams. The central question is not whether the organization can produce a model. It is whether leadership can use that model to make better trade-offs early enough to matter.

Before approving a major defense bid, senior leaders should usually ask: which assumptions drive most of the cost; which supplier positions are still unproven; what learning curve or yield improvement is embedded in the price; what portion of the margin depends on post-award recovery; and what evidence supports those assumptions from actual production or program history?

For companies pursuing major proposals, reviewing sole-source positions, or trying to improve estimating discipline, the Umbrex Aerospace & Defense Practice can help identify independent consultants with experience in proposal strategy, cost estimating, supplier should-cost analysis, basis-of-estimate development, and documentation for Defense Contract Audit Agency (DCAA) and Defense Contract Management Agency (DCMA) reviews.

How organizations can get started or improve

• Focus on the highest-value bids first. Start with programs where supplier content, engineering uncertainty, or fixed-price exposure is material.
• Standardize model structure. Align the model to the work breakdown structure, recurring versus nonrecurring logic, and a common BOE format.
• Build a usable actuals library. Capture labor hours, yields, test effort, supplier performance, and rate history from completed work.
• Develop supplier clean-sheet capability. Even a simple driver model can materially improve negotiations on machined parts, electronics assemblies, or service subcontracts.
• Establish pricing governance. If leadership chooses to bid below internal should-cost, make the gap explicit and assign an execution plan.
• Close the loop after award. Compare proposal assumptions with actual performance so the next bid starts from evidence, not memory.

Related concepts and useful distinctions

Should-cost versus price-to-win: should-cost asks what the work ought to cost the bidder; price-to-win asks what market price may be needed to win. A sound bid strategy understands both.

Should-cost versus cost realism: cost realism is an evaluation concept used by the government in certain procurements to judge whether proposed costs are realistic for the work. A contractor’s should-cost model is its internal management tool.

Should-cost versus will-cost: in DoD acquisition, will-cost is a program baseline or expected cost position; should-cost is a management effort to beat that baseline. In industry bidding, the term usually means the achievable internal cost view.

Should-cost versus historical pricing: prior prices are useful inputs, but they are not a substitute for understanding the current technical, quantity, schedule, and supplier drivers behind cost.