A CLIN Is More Than a Billing Line: GAO Says Contract Architecture Can Improve Contractor Accountability

Contract line items are sometimes treated as administrative devices used principally to organize funding and invoicing. A new GAO report demonstrates why that view is too narrow.

The way an agency constructs its CLINs can determine how effectively it sees performance, measures results, allocates fee, and holds a contractor accountable.

On September 23, 2026, GAO released a report examining the National Nuclear Security Administration’s use of contract line items within its management-and-operating contracts. The issue is consequential: NNSA spends more than $20 billion annually across nine M&O contracts covering the government-owned, contractor-operated facilities that comprise the nuclear-security enterprise. In fiscal year 2025 alone, NNSA spent almost $24 billion under these arrangements.

Historically, NNSA has relied upon broad M&O contracts covering extensive portfolios of work at individual sites. Beginning in 2014, the agency introduced separate line items for selected projects to improve visibility into specific work.

But GAO found that NNSA has used the tool relatively sparingly.

Of 21 capital-asset projects with approved performance baselines as of June 2026, only five were covered by separate contract line items. Those included major work at the Y-12 National Security Complex, Savannah River Site, and Sandia National Laboratories.

Why does the structure matter?

GAO found that separate line items can improve procurement-data transparency and permit NNSA to create project-specific fee plans and contractor performance evaluations for particularly high-risk or high-value work. That can make it easier to isolate whether a contractor is meeting cost, schedule, and performance expectations for an individual project rather than allowing results to disappear inside a much larger contract portfolio.

Separate CLINs are not costless. Agency officials and contractors told GAO that administering additional fee plans and performance evaluations requires additional resources.

The problem, according to GAO, is that NNSA has not documented consistent criteria for determining when those additional costs are justified.

Officials reported considering factors such as project cost, complexity, and dedicated appropriations, but those considerations were not formalized. NNSA also had not systematically documented lessons learned from prior use of separate line items. GAO recommended that the agency address both deficiencies.

The contractor lesson extends beyond nuclear construction.

Contract architecture determines risk architecture.

A separately structured CLIN can isolate price, funding, deliverables, fee, acceptance criteria, schedule, or performance evaluation. Conversely, placing materially different work inside a single broad line item can obscure assumptions and make it harder to determine which party bears the economic consequences when circumstances change.

That lesson applies at both ends of federal contracting. A poorly constructed CLIN can prevent a small contractor from recovering fixed costs when estimated quantities decline. On a multibillion-dollar M&O contract, inadequate line-item structure can make it harder for the Government to isolate performance and accountability.

Contractors should therefore analyze CLIN architecture during solicitation review—not after award. The question is not merely how the Government intends to pay.

It is what the structure says about risk, measurement, funding, incentives, and accountability.

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Disclaimer:
This article is provided for general informational and educational purposes only and does not constitute legal, accounting, pricing, or procurement advice. Appropriate CLIN structure depends on the contract type, statement of work, funding, pricing methodology, deliverables, acquisition strategy, and applicable regulations.