{"id":74573,"date":"2026-09-04T16:52:18","date_gmt":"2026-09-04T19:52:18","guid":{"rendered":"https:\/\/a3aengenharia.com\/?post_type=articles&p=74573"},"modified":"2026-09-04T16:52:18","modified_gmt":"2026-09-04T19:52:18","slug":"public-works-terms-of-reference-avoid-contract-amendments","status":"publish","type":"articles","link":"https:\/\/a3aengenharia.com\/en-us\/content\/technical-articles\/public-works-terms-of-reference-avoid-contract-amendments\/","title":{"rendered":"How to Write Public-Works Terms of Reference That Do Not Turn Into Avoidable Contract Amendments"},"content":{"rendered":"\n

Well-structured Terms of Reference for public works<\/strong> do not eliminate the legal possibility of contract amendments, because changes may result from supervening facts, legitimate needs of the Administration or events provided for under the contractual regime. What they do is reduce avoidable amendments<\/strong>: those arising from a poorly defined object, inconsistent design and budget, quantities without traceability, omitted interfaces, vague measurement criteria, undefined responsibilities or execution conditions discovered only after contracting.<\/p>\n\n\n\n

In practice, writing Terms of Reference for a public work means transforming a public need and an engineering solution into a set of obligations that the market can understand, price, execute and demonstrate<\/strong>. This requires much more than filling out a template. The document needs to align with the Preliminary Technical Study, the applicable Basic Design or Detailed Design, the estimated budget, schedule, risk matrix, tender documents and draft contract. If each annex describes a different reality, the procurement transfers into the contract an uncertainty that should have been resolved during the preparatory phase.<\/p>\n\n\n\n

Under the current framework of Law 14,133, Brazil\u2019s Attorney General\u2019s Office uses a unified Terms of Reference template for services, engineering services and construction works and emphasizes that Terms of Reference and Basic Design perform different functions<\/strong>. Basic Design is an engineering document; the Terms of Reference structure the procurement in its technical-administrative dimension and need to correctly incorporate what the designs, studies and preparatory decisions have established. Therefore, good Terms of Reference do not \u201ccompensate\u201d for an immature design: they make a solution contractible when it already has a technical basis sufficient for the chosen regime.<\/p>\n\n\n\n

Public-works Terms of Reference are not the design, but they need to align with it<\/h2>\n\n\n\n

One of the most common mistakes in engineering procurement is trying to make the Terms of Reference perform functions that belong to the design. The result is often a long document full of broad statements but without enough information to resolve engineering decisions.<\/p>\n\n\n\n

Brazil\u2019s Attorney General\u2019s Office itself highlights, in its guidance for Law 14,133 templates, that the old simplified association between Terms of Reference and electronic bidding on one side, and Basic Design and other procedures on the other, is no longer appropriate. The documents have distinct functions. In construction works and special services, the Terms of Reference remain relevant as a procurement artifact, while Basic Design retains its own engineering content.<\/p>\n\n\n\n

This distinction should appear in practice:<\/p>\n\n\n\n

Document<\/td>Primary function<\/td>Question it should answer<\/td><\/tr>
ETP<\/td>decision on the solution<\/td>why contract and which solution best meets the need?<\/td><\/tr>
Basic Design<\/td>technical definition<\/td>what will be built and under which technical conditions?<\/td><\/tr>
Detailed Design<\/td>detailing for execution<\/td>how will the solution actually be executed?<\/td><\/tr>
Budget<\/td>reference-price formation<\/td>how much does the defined solution cost?<\/td><\/tr>
Terms of Reference<\/td>procurement structure<\/td>what must the contractor deliver, how must it execute, measure and demonstrate?<\/td><\/tr>
Tender documents<\/td>rules of the competition<\/td>how will the market be selected and which rules will govern competition?<\/td><\/tr>
Contract<\/td>binding obligations<\/td>how will responsibilities, payments, risks and changes be managed?<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n

The article on Engineering Terms of Reference<\/a> addresses the general structure of this document. In public works, the additional challenge is maintaining consistency among all technical and contractual annexes.<\/p>\n\n\n\n

What Law 14,133 requires to be defined during the preparatory phase<\/h2>\n\n\n\n

Law 14,133 structures the preparatory phase as a planning process. Article 18 requires compatibility with the Annual Procurement Plan when one exists and with budget laws, as well as consideration of technical, market and management issues capable of affecting the procurement.<\/p>\n\n\n\n

Elements of this preparation include describing the need based on the ETP, defining the object through the appropriate document, execution and payment conditions, guarantees, acceptance, estimated budget, tender documents, draft contract, execution regime, procurement procedure, award criterion and bidding mode.<\/p>\n\n\n\n

This shows why public-works Terms of Reference cannot be written in isolation. They are one component of a decision system.<\/p>\n\n\n\n

The Preliminary Technical Study for construction works and engineering services<\/a> should explain the need and the chosen solution. The Terms of Reference receive that decision and convert it into a contractible scope. If the ETP has not yet stabilized the problem and the solution, the Terms of Reference author will be forced to make decisions that belonged to an earlier stage.<\/p>\n\n\n\n

Avoidable contract amendments usually begin before the contract is signed<\/h2>\n\n\n\n

Contract amendments formally appear during execution, but many of their causes are introduced before the tender.<\/p>\n\n\n\n

An underestimated quantity may originate in an incomplete record survey. A scope change may result from an omitted requirement. A solution change may arise from a Basic Design incompatible with actual conditions. A time extension may begin with a work front that was never effectively available. A new item may appear because an interface between two suppliers was assigned to nobody.<\/p>\n\n\n\n

The control point, therefore, is not to write a clause saying that \u201call necessary services are included.\u201d It is to remove material uncertainty from the object before competition.<\/p>\n\n\n\n

The content on Contract Amendments in Construction Works and Engineering Services<\/a> shows how changes are handled during the contract. The Terms of Reference act one stage earlier: they should reduce avoidable triggers that would lead to that treatment.<\/p>\n\n\n\n

Start with the need and expected result, not a list of services<\/h2>\n\n\n\n

Weak Terms of Reference often begin by copying a bill of quantities or the description of a previous procurement. This creates scope without context.<\/p>\n\n\n\n

The technical opening should make clear:<\/p>\n\n\n\n