A New Taxonomy of Vagueness in Contracts

This contains my first attempt at expressing something I’ve been mulling over for a while—the notion of “floating vagueness.” I’m prepared for it to end up in the dustbin. [Updated 25 June 2016: Hey guess what, it did end up in the dustbin! I found a way to express more simply the concepts I was groping for. My revised analysis will appear soon in an article. Don’t bother reading this post.]


One source of uncertain meaning in contracts is vagueness. With vagueness, whether a given standard is met is a function of the circumstances. For example, the word promptly is vague. How fast a contract party has to act to comply with an obligation to do something promptly is a function of what would be reasonable under the circumstances. There’s no specific deadline.

It follows that with vagueness comes the possibility of dispute. A contract party under an obligation to do something promptly might act fast enough that no one could reasonably say that they hadn’t acted promptly. But the longer they take, the greater the likelihood of the other party’s deciding that they hadn’t acted promptly.

That being the case, it would seem sensible to be specific instead of vague. Saying, for example, no later than five days after instead of promptly after allows you to avoid the possibility of dispute.

But drafters use vagueness whenever lack of control (over the future, over someone else’s conduct) renders precise standards unworkable. For example, if a provision requiring reimbursement of legal expenses might apply to a broad range of litigation, from the trivial to the catastrophic, it might make sense to express a cap not as a specific amount but instead by referring to reasonable legal expenses.

Vagueness can also be expedient if addressing an issue precisely would make negotiations longer or more contentions than one or both parties want.

Reasonable-Person Vagueness Versus Floating Vagueness

One can discern two kinds of vagueness. There’s vagueness associated with the adjectives reasonable, prompt, material, negligent, satisfactory and workmanlike (among others) and any related adverbs. Vagueness using such words is assessed using a reasonable-person standard. That’s self-evident in the case of reasonable and reasonably; in the case of the other words, it’s a function of caselaw.

But other vague words appear not to require a reasonable-person standard. For example, the adjectives fast, similar, substantial, tall, extreme, and the related adverbs.

Determining whether, for example, someone is tall necessarily involves considering the circumstances, namely whether you’re dealing with a group of preschool children or a group of basketball players. But beyond that, it’s not clear what the basis would be for determining the minimum height for being tall.

Similarly, where on the spectrum from “nothing” to “all” does the word substantial fall? Who knows. (The phrase substantially all is anchored at the “all” end of the spectrum, which reduces the scope for dispute, although the question what substantially all means nevertheless fuels its fair share of litigation.)

To distinguish this kind of vagueness from vagueness assessed using a reasonable-person standard, I propose referring to it as “floating vagueness.” Words associated with reasonable-person vagueness express established legal standards that you either meet or don’t meet. By contrast, words associated with floating vagueness express other attributes that don’t have those legal connotations, so they don’t have a reasonableness standard attached.

Whether a standard based on reasonable-person vagueness has been met might be far from clear cut— reasonable-person vagueness fuels plenty of litigation. But floating vagueness incorporates an extra measure of uncertainty. So use reasonable-person vagueness only when being precise doesn’t make sense or exacts too great a negotiation cost, and try not to use floating vagueness at all.

Gradations of Vagueness

The notion of gradations in vagueness is an unhelpful one.

It’s on display in use of negligent and grossly negligent. If negligent behavior is unreasonable behavior, grossly negligent behavior is … really unreasonable behavior. How bad does behavior have to be to be grossly negligent? Who knows. In effect, negligent expresses reasonable-person vagueness whereas grossly negligent expresses floating negligence.

I have encountered the suggestion that even worse than grossly negligent is reckless, and worst of all is wanton. There’s nothing to support that. You have negligent and, if you wish, whatever is worse than negligent. Exactly how you express the worse-than-negligent standard is unlikely to matter, but grossly negligent is probably the most popular choice.

The biggest misconception regarding gradations of vagueness is the notion of a gradation of standards featuring efforts (or in England and some other Commonwealth jurisdictions, endeavours), with best efforts being the most exacting standard. It fails as a matter of semantics and contract logic. Furthermore, U.S. courts have said, with essentially one voice, that all efforts standards mean the same thing—reasonable efforts. Courts in other jurisdictions, notable England and Canada, have tried to articulate distinctions but have failed spectacularly.

About the author

Ken Adams is the leading authority on how to say clearly whatever you want to say in a contract. He’s author of A Manual of Style for Contract Drafting, and he offers online and in-person training around the world. He’s also chief content officer of LegalSifter, Inc., a company that combines artificial intelligence and expertise to assist with review of contracts.

12 thoughts on “A New Taxonomy of Vagueness in Contracts”

  1. My immediate reaction, without studying the case law, is that I doubt whether English law applies a reasonable-person standard to all the items in your first category. In other words, I doubt whether the judge, when deciding whether the standard has been met, is explicitly looking to see what a reasonable person would do. Instead, he may focus on the words used and just decide the matter.The word “prompt” particularly prompts this thought in light of case law on whether a party has responded quickly enough in response to court orders. “Satisfactory quality” is, of course, the English equivalent of “merchantable quality”, and I don’t know whether that is decided by explicit reference to the reasonable person or just what the judge thinks. Some other words in your list, eg reasonable, negligent, seem more likely to be decided by reference to a reasonable observer.

    On “substantial” I recall looking at the leading English cases on whether a rent increase had been substantial. Although not always done in the cases, I worked out the percentage increase at issue. The numbers varied but it was striking that they hovered around 15% – whether the judges realised this, or it was just an instinctive “feel” that led them in this direction, I don’t know, but I suspected the latter.

    I suspect that most of the words that you mention leave a huge amount of discretion to the judge to decide what he thinks is just in the individual case.

    • As usual, I’m concerned primarily with what those drafting, reviewing, and negotiating contracts make of contract prose. Whatever courts make of it after the fact is of lesser interest: I’m in the business of avoiding fights, not winning them.

      In this case, my starting point is that promptly is easier to work with than is, say, tall. Everything else represents my attempt to create a rationale for that.

      My ear has stood me in good stead over the years, so I was willing to float this trial balloon. But if someone can convince me that my ear is playing tricks on me, I’ll happily drop the whole idea. But by itself, saying that this idea is a nonstarter (as AWB does) perhaps isn’t enough.

      Or someone might be able to offer an alternative explanation for the difference that I’m wrestling with.

      • Ken,

        I feel as though you are trying to define something like a subjective reasonableness, as opposed to objective reasonableness (reasonable person standard). By that I mean, the context of the parties and the particulars of the transaction become important when dealing with floating vagueness. Floating vagueness, to be acceptable as a drafting tool would seem to require either a prior foundation of understanding between the parties or a reliance on parole evidence. The latter seems overly dangerous and almost guaranteed to lead to dispute. The former seems to almost require the parties to be in the same industry with the same understanding of terms of art used in that industry that floating vagueness has some mutual definition, i.e. what tall means in the context of basketball players vs. for example, soccer players. But then have you not returned to objective reasonableness, i.e. what would a reasonable person in the position of the parties think the provision means.

        • Thanks for chiming in.

          I have yet to find a context where subjective-versus-objective exists, unless it’s explicit that a party’s own views prevail, no matter how unreasonable. It doesn’t apply here.

          And I’m not suggesting that floating vagueness is a good idea. In fact I say you should steer clear of it.

          What I’m groping at is that because a word like tall isn’t a reasonable-person standard, you have no way to anchor it on the height spectrum.

  2. 1/ With trepidation at putting myself at the opposing end of the spectrum from Mark Anderson, I think all the examples of ‘floatingly vague’ words in the post, including (in alphabetical order) extreme, fast, similar, substantial, and tall, fall under a reasonableness standard, so the category of ‘floating vagueness’ is a nonstarter.

    2/ To the extent that words are ‘floatingly vague’ when they express nonspecific attributes not accessible to reason, query whether they belong in a contract.

    3/ If a ‘floatingly vague’ term becomes the subject of dispute, and is interpreted to mean ‘whatever a judge thinks is right’, that voids any chance of appeal, because that interpretation makes the judge a final arbiter with no standard by which an appeals court could find the decision erroneous.

    4/ Indeed, I wonder whether a court might not reject such a case as a request that the court write the parties’ contract for them rather than determine the intent they expressed by the words they used.

    • AWB:

      I’m not following your first argument. I think Ken’s point is that courts have sufficiently focused on words that are based on a reasonable-person standard that we can talk intelligently about how a court would think through what is reasonable under a variety of circumstances. I don’t think we really can about the word “tall,” for example. Are you saying that there is a body of caselaw that tells me how courts will construe the word “tall” under a variety of circumstances? Or are you saying “tall” means “whatever a reasonable person would think is tall under the circumstances”?


      • The latter: ‘tall’ means what a reasonable person acting reasonably would think is tall under the circumstances. If a body of caselaw has reliably defined ‘tall’, then it’s no longer vague.

        So I’m not seeing a category of vague expressions the meaning of which can’t be found by the reasonable person standard, but only by some other, non-reasonable standard.

        • AWB:

          I think there’s a difference, but it might only be where I start and no where I end. For the phrase “promptly do an act,” we lawyers would mean “do the act within the amount of time that a reasonable person acting reasonably would do it.”

          Your proposal seems one abstraction removed. Instead of observing what reasonable people acting reasonably do, we ask what reasonable people acting reasonably think. The difference between doing and thinking is stark in areas such as behavioral economics. What people think (or at least, what they say they think) is not consistent with their actions.

          So my objection to your solution is that you can’t directly observe the meaning of “tall” in the actions that reasonable people take acting reasonably. Instead, you’d have to ask them or survey them.

          Of the words in Ken’s second list, the only one that does not ass this test for me is similar. I can express this as a reasonable-person test: two things that a reasonable person acting reasonably would treat as the same.

          You might argue that you can express the same thing for tall: anything that a reasonable person acting reasonably would treat as tall. The problem I have with that approach links back to Ken’s suggestion of how to cure it. You can’t know whether reasonable people acting reasonably would treat something as tall without knowing the exact purpose. So, one might say, “tall for the purpose of determining whether the applicant can play in the NBA.” We’ve now supplied a standard. But I’m still note sure that it’s definite enough. Am I shooting at the median of NBA players or the first standard deviation up, or what?

          Assuming though that the NBA language is sufficient, the next logical objection is that the reasonable person standard always includes something like “under the circumstances.” So, doesn’t that just import the reason? Maybe. That’s where I have to stop and think about it more. It seems like the reality is we say things like “use reasonable efforts to file the paper” — and “to file the paper” provides what the standard is.

          So my final answer might be that all vague language needs to be associated with some language that sets a purpose or standard by which the vague language is implicitly defined, and that if you are shooting at anything other than the middle, you need to be explicit about it. Maybe. I think.


          • I haven’t thought about your distinction between what a reasonable person would do and what a reasonable person would think. Assumed without thinking that they were the same. Will chew on it.

  3. Since the ostensible objective of a court interpreting a contract is to ascertain what the parties intended, you would expect that a court would conclude that vague terms that have a considerable history of decisional gloss, which are mostly the “reasonable-person” terms Ken mentions, would have those meanings unless there were a contra-indication in the document. Conversely, where terms don’t have that kind of gloss, or aren’t amenable to a universal standard of analysis, which would be the floating vague terms (hats off to Ken for the crypto-pun in that expression), must be interpreted in accordance with how the parties, in the transaction at issue, thought of them. That’s exactly the type of situation that gives rise to the exceptions to the parol evidence rule, so off we go to the ol’ fishing hole. And that’s why the parties should avoid putting themselves and the courts in that position by avoiding floating vagueness, or if it’s unavoidable, they should provide enough context, perhaps in the recitals, to guide future interpretation.

    One term that might be thought floatingly vague is the substitute for “prompt” used by the UCC, which is “seasonable.” I’ve always liked that word, but have a devil of a time explaining it to anyone. Maybe the drafters hoped there would be enough case law developing under it to give it substance. Has there been? And does it make sense to use the term in contracts that are not governed by the UCC?

    • I’m mulling over whether it isn’t just decisional gloss that distinguishes my two categories. Perhaps there’s something about, for example, assessing the time taken to do something that’s more amenable to a reasonable-person standard than is, for example, determining whether someone is tall.


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