The statement of work: the most important contract topic nobody writes about

At 09:04 universal time on 23 September 1999, radio contact with the Mars Climate Orbiter breaks off, 49 seconds earlier than calculated. The probe has nine months of flight and 669 million kilometers behind it and is due to swing into orbit that morning. Instead, it dips into the atmosphere 57 kilometers above the Martian surface. Below 80 kilometers, it cannot survive. The signal never returns.¹

NASA’s investigation board found the cause in a single file on the ground. The manufacturer’s software delivered the thruster data in pound-seconds. The navigation software at the Jet Propulsion Laboratory calculated in newton-seconds, exactly as the interface specification required. A factor of 4.45, for nine months, on every single course correction. Both teams were among the best in the world. Both worked flawlessly within their own frame. Nobody caught the error, because each side believed the other had understood. The price of that illusion: the probe of a program NASA had put at 235.9 million dollars, launches not included.²

“The great enemy of communication, we find, is the illusion of it.” The line dates from 1950 and belongs to the journalist William H. Whyte. To this day it mostly circulates as a George Bernard Shaw quote. Of all sentences, the most famous line about misunderstanding has been misattributed for seven decades.³

Contracts fail the same way. After twenty years of negotiating and drafting them, I am convinced: the most expensive contract problem is not in the fine print. It arises before the first clause is drafted, when the parties believe they have agreed on the performance and have in fact been talking past each other. Everyone polishes the wording of the legal clauses. The description of the performance — the actual deal — stays vague. And because the topic belongs to no discipline, almost nobody writes about it.

The wrong front

Watch an international contract negotiation and you will see precision work on the wrong front. Days are spent fighting over whether it must be “best efforts,” “reasonable best efforts,” or “commercially reasonable efforts.” The liability exclusion stacks synonyms: “indirect, incidental, special, or consequential damages.” I have sat through rounds fought with devotion over such formulas while the statement of work traveled through every draft as “Exhibit 1: to follow.” The software world has a name for this pattern: bikeshedding, after Parkinson’s law of triviality. The debate gathers where everyone can weigh in, not where the risk sits.

Kenneth Adams, author of the leading style manual for English contract language, has positioned his work explicitly as an alternative to the dysfunction of traditional contract drafting.⁴ He is right. But the real dysfunction sits one level higher: not in how something is worded, but in whether it is clear what is owed at all. Most contracts do not fail on what they say; they fail on what both sides took for granted.

How high the stakes are became visible in 2021, in the dispute between the European Commission and AstraZeneca over vaccine deliveries — over precisely the formula whose wording is otherwise fought over for days: before the Brussels civil court, with 870 million euros at stake, the case turned on the statement of work, namely what the “best efforts” promise actually obliged the supplier to deliver.⁵ The formula had become the statement of work, and nobody had said what it meant.

The Contract

Definitions

Best efforts

Consequential damages

Warranty

Limitation of liability

Governing law, jurisdiction

every word negotiated

Exhibit 1: Statement of Work[to follow]This is where disputes begin

Why the topic falls between the disciplines

Circle of competence

That is what Warren Buffett and Charlie Munger call it: know where the boundary of your own ability runs, and act inside it. In contract negotiations I regularly watch the inversion. The engineers debate warranty and liability with enthusiasm while the technical parameters, their home turf, remain incomplete. The lawyers treat the statement of work as a technical annex: “Exhibit, comes from the business side.” Each discipline leaves its circle of competence precisely where it is most expensive. And nobody feels responsible for the interface.

The teams do not talk to each other

Sales promises, engineering calculates, legal drafts, often in sequence rather than together, and without a shared knowledge system. What the customer actually needs gets lost between the stations. The sales director of an international company told me after tough negotiations: “We are dysfunctional. But the others are more dysfunctional.” He meant it as consolation. It is a precise description of most contract processes: the winner is not the side that communicates well, but the side that communicates less badly.

Same words, different languages

International contracts are negotiated in English by people whose native language is rarely English. “Acceptance,” “commissioning,” and “availability” mean something different to each side, shaped by legal system, industry, and culture. In “The Culture Map,” Erin Meyer shows that Germany and the United States are among the cultures that make communication most explicit, while many business partners around the world are used to reading the essentials between the lines. Her rule for multicultural teams fits in one line: “Multicultural teams need low-context processes.”⁶ A contract is exactly that: the low-context process of a deal. It works only if it spells out what one of the two sides takes for granted.

The result: the statement of work belongs to nobody. The engineers consider it legal paperwork, the lawyers consider it engineering, management considers it detail. On liability clauses, the literature fills shelves. On the craft of describing a performance clearly, there is next to nothing. That is why it is the most important contract topic nobody writes about.

What is at stake

The illusion of agreement is stable as long as nothing happens. It holds until the first real test: the machine runs, but at a different throughput than the buyer expected. The software works, but the interface to the legacy system was “obviously included.” From that moment, what decides is no longer the shared understanding that never existed, but the text of the contract.

And that text is interpreted under rules that surprise many. Before a German court, what counts is not what you meant but how an objective recipient was entitled to understand the declaration (Sections 133 and 157 BGB). The statement of work also defines what a defect is (Section 434 BGB): without an agreed specification, you will later argue about what is “customary” and what the buyer “could expect.”

If the contract is governed by English or US law, it gets stricter. The parol evidence rule largely cuts off recourse to earlier understandings, emails, and drafts, and the customary entire agreement clause draws the same line contractually: what is not in the document does not exist. The CISG is more generous and expressly allows negotiations and practices to be used in interpretation (Article 8(3) CISG). Do not rely on it: whoever invokes something that is not in the contract is fighting uphill.

There is a twist that even many lawyers have never seen up close: the legal clauses of standard contracts face strict judicial review under German standard-terms law, and German courts strike down unreasonable clauses routinely. The actual statement of work, by contrast, is not subject to that strict review of content (Section 307(3) BGB; settled case law, e.g. BGH, judgment of 5 October 2017 – III ZR 56/17). What you describe as the performance, or fail to describe, no court will test for reasonableness. That is opportunity and risk at once. Opportunity, because the statement of work is the most powerful drafting tool that content review leaves untouched: what is not owed cannot be breached, and a precise statement of work often limits liability more effectively than the liability clause that fails under Section 307 BGB. Risk, because the flip side holds: nobody will repair this part of the contract for you.

What helps

First, the sequence. I keep being instructed to “go ahead and draft the contract” while the essential content, above all the statement of work, is still open. That is the Mars Climate Orbiter sequence: launch first, talk about units later. The efficient path runs the other way, content first, then wording; every draft before that is a draft of the misunderstanding. Four steps have proven themselves.

Understand the context before you draft

What is the performance supposed to deliver in the customer’s daily operations? How is success measured, by whom, with which method? The Mars test is banal and hard at once: are the units defined? Metric, measuring method, reference conditions, tolerances. The orbiter was not lost to physics, but to a missing agreement on units.

Get the disciplines around one table

Engineering, sales or procurement, and legal discuss the statement of work together, not in sequence. One shared hour before the first draft saves weeks of negotiation rounds and, in the worst case, years in court. To make that repeatable you need a system: defined terms, maintained templates, working knowledge management.

Concentrate on what matters

Do not regulate every eventuality; regulate the parameters the deal economically depends on: quantities, qualities, dates, delivery terms (Incoterms), interfaces, duties to cooperate, acceptance criteria. A statement of work that clearly covers the important things beats one that covers everything.

Clear, complete, no room for interpretation

Every technical term is defined or made measurable. The test: would a third party who knows none of the preliminary talks understand this description the same way you do? If two readings are possible, the one argued in a dispute will be the one that hurts you.

The object lesson is the popular formula “fit for purpose”: it sounds precise and is the opposite. “Purpose” can reach beyond the agreed performance values to anything the customer mentioned as an intended use in the course of the negotiations; under English law, fitness for purpose may even be read into the contract as an implied term unless expressly excluded. If you cannot avoid the formula, tie “purpose” expressly to the specifications defined in the contract.

And the lawyer? His place is not the legal column but the interface. Lawyers are the one discipline at the table whose craft is making things explicit; that is what they should be used for, not only for the choice of law. Honesty also means: whether a technical specification is complete, I cannot guarantee — only your engineers can. What I can do: ask the questions that expose the gaps, translate between the disciplines, and make sure the answers end up in the contract rather than in the minutes of a conference call.

Conclusion

The Mars Climate Orbiter did not fail on bad work. Both teams delivered, each flawless by its own standards. The probe was lost at the interface, to the illusion of having understood each other. Contracts fail the same way: rarely on the clause everyone fights over, almost always on the performance nobody talked about. By all means polish the wording of your next contract. But start with Exhibit 1.

Cover image: the Mars Climate Orbiter being mated to the third stage of its Delta II launch vehicle, Kennedy Space Center, November 1998. Image: NASA (KSC-98pc1736).

Notes

1. NASA, Mars Climate Orbiter Mishap Investigation Board, Phase I Report, 10 November 1999: loss of signal on 23 September 1999 at 09:04:52 UTC, 49 seconds earlier than predicted; reconstructed periapsis of 57 km against a survival limit of roughly 80 km. ↩

2. Root cause per the Phase I report: thruster data in the ground file “Small Forces” in pound-seconds instead of the “specified and expected units” of newton-seconds, off by a factor of 4.45. Cost per NASA: 193.1 million USD for development and 42.8 million USD for mission operations, 235.9 million USD in total for the twin program of Mars Climate Orbiter and Mars Polar Lander, launch vehicles not included (JPL press kit, September 1999; likewise the 1998 Mars Missions press kit). ↩

3. William H. Whyte, “Is Anybody Listening?”, Fortune, September 1950; on the widespread misattribution to Shaw: Quote Investigator, 31 August 2014. ↩

4. Kenneth A. Adams, A Manual of Style for Contract Drafting, 5th ed. 2023; overview at adamsdrafting.com. ↩

5. Tribunal de première instance francophone de Bruxelles, judgment of 18 June 2021 – 2021/48/C, CISG-online 5607; at issue was the “best efforts” clause of the vaccine supply agreement between the European Commission and AstraZeneca AB. ↩

6. Erin Meyer, The Culture Map, PublicAffairs 2014, pp. 34 et seq. (low-context ranking) and p. 55 (rule for multicultural teams). ↩

Reference: Poleacov, P. (2026). The statement of work: the most important contract topic nobody writes about. INN.LAW. https://inn.law/en/perspectives/statement-of-work/

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