How does an SOW differ from a capitolato tecnico?

They serve the same purpose: describing what the supplier must deliver. Capitolato tecnico is the name Italy's Public Contracts Code (Legislative Decree 36/2023) uses for services and supplies, where it is one of the minimum project contents listed in Annex I.7. In the capitolato the contracting authority also sets the technical arrangements and timing of the verifica di conformità, the acceptance check (article 116(8)). SOW is the term used in international project management.

What should the SOW for an AI project include?

At least the expected outcome, which data the client provides and in what condition, the acceptance criteria with the method and sample used to measure them, the procedure for requesting and pricing changes, and a list of what is excluded. A list of activities and person-days describes the supplier's effort, not the outcome to be delivered.

Who writes the SOW, the client or the supplier?

Either one can. US federal procurement rules (FAR 37.602) allow both routes: the agency prepares the performance work statement, or it sets only the objectives in a statement of objectives and leaves the bidder to draft the PWS. Either way, buyers should review it as their own document, because it is the text on which acceptance will be decided.

What is a statement of work (SOW) and what should it include?

A statement of work (SOW) is the document that sets out what a supplier must deliver: the outcome, data, acceptance criteria, change process and exclusions.

A statement of work (SOW) is the document that sets out what a supplier must deliver: products, services or results, described in plain prose. The Lexicon of the Project Management Institute (PMI), the international association of project managers, defines it in just those terms, as a narrative description of what the project will deliver. In practice an SOW goes out with a request for proposal and then becomes part of the contract, where it is the yardstick for judging whether the work is finished. For a data or AI project it should cover at least five things: the expected outcome, who provides which data, the acceptance criteria and how they are measured, the procedure for changes, and a list of what is left out. An SOW that only lists activities and person-days describes the supplier's effort, not the outcome you are buying, and leaves open the very argument it is meant to settle.

See also: RFI vs RFP vs RFQ · RFI, RFP and RFQ are supplier requests that differ by how much the buyer knows: ideas on an open problem, proposals on requirements, prices on a closed spec.

Results, not hours

US federal procurement rules (FAR) offer the clearest benchmark for how to write one. FAR 37.602 asks agencies to describe the work in terms of the required results rather than how it is to be done or the number of hours to be provided, and to make performance assessable against measurable standards. FAR 2.101 calls such a document a performance work statement (PWS): a statement of work that describes the required results with measurable outcomes. That section also defines the statement of objectives (SOO), in which the government sets only the objectives and leaves it to bidders to propose how to meet them. These are US rules, useful for comparison. The same distinction also bears on the choice of contract: an SOW written in person-days tends to lead to a time and material contract, even when the buyer expects an outcome.

The capitolato tecnico in Italian public procurement

In Italy's Public Contracts Code (Legislative Decree 36/2023), the equivalent document for services and supplies is the capitolato tecnico (technical specification). Article 41(12) provides for a single design stage for services and supplies and refers to Annex I.7, whose article 4-bis lists the minimum contents of the project: a general explanatory report, the capitolato tecnico and a cost estimate. Article 116(8) adds that the capitolato sets the technical arrangements and timing of the verifica di conformità, the check by which the public buyer (the stazione appaltante) confirms that the work complies with the contract.

An enterprise example

A services company wants an AI assistant that routes customer emails to the right department. The supplier's first draft of the SOW lists 120 person-days of analysis, development and testing. The procurement manager rewrites it around the outcome: incoming emails are routed automatically, at an agreed accuracy threshold measured on a sample of real emails drawn by the company. The new version also states who provides the email history and by when, how a change is requested and priced, and what is out of scope, such as automatic replies to customers. When a new type of request emerges halfway through, it is handled as a priced change and never turns into scope creep.

Why it matters for decision makers

The SOW is the text everyone goes back to in every later dispute: whether the work is finished, whether a request is a change to be paid for, whether the supplier has delivered. When the scope is vague, the conflict surfaces at the end of the project, with the budget already spent and little time left. Buyers are better off writing it before the request for proposal goes out, even if the supplier completes it later, because acceptance criteria, data responsibilities and project boundaries are easier to negotiate while bids are still competing.

This entry is informational and does not constitute legal advice: to draft a specific capitolato or contract, involve your legal counsel.