I was reading a letter I got from an old friend, back in 1998, and at a certain point she wrote:

"Our period of greatest prosperity were those eleven years when Thatcher was in office."

Is this correct, or just acceptable? In speech and in writing?

  • Related: Singular Is/Are Plural?
    – RegDwigнt
    Commented Oct 27, 2014 at 23:41
  • 1
    Depends on whether you see the timespan as a continuous, cohesive, whole (i.e. "a period" [singular]) or as a collection of discrete units (i.e. "those eleven years" [plural]). Same idea when people debate about "Data is/are".
    – Dan Bron
    Commented Oct 28, 2014 at 0:09
  • But data is always plural, the singular being "datum", which nobody uses anyway.
    – Centaurus
    Commented Oct 28, 2014 at 0:14
  • @Centaurus, yes, that's the argument prescriptivists make (or made, anyway), but then they also used to make the argument that we shouldn't split the infinitive in English because the Romans didn't in Latin. People do use data in the singular, particularly when they think of it as a mass noun. In contexts where they think of it as a count noun (multiple, discrete, piece of information), they use data in the plural. Same idea with your timespan above: whether to use the singular or plural depends entirely on how you envision the time (a singular period or eleven discrete years).
    – Dan Bron
    Commented Oct 28, 2014 at 0:20
  • 1
    @Centaurus, have you ever suffered "data loss"? If someone was compiling a database (let's say of English usage), would you ask "How many data are in your database"? How big is your hard-drive? Oh, 100 gigabytes? So how many data can it hold? (FYI, when I read that FDA motto, "data" scans as singular, mass-noun to me, as in "everyone else must bring cash"). In other words, "data" is a synonym of "information", at least in the US. But that's neither here nor there, your question is about time, which indeed can be a mass or count noun (a span, 6 months).
    – Dan Bron
    Commented Oct 28, 2014 at 0:35

3 Answers 3


The answer to your question is that "were" is incorrect and unacceptable here. The subject is singular and consequently it needs a singular verb. It is not acceptable to use a plural verb here even in casual speech, which isn't to say it wouldn't be understood, it would just not be grammatically correct.

For sure there are alternative plural subjects you could use. For example:

Our years of greatest prosperity were those eleven when ...

Our times of greatest prosperity were those eleven years when...

There are cases when it is less clear. For example: "The football team is running on the field" or "the football team are running on the field." Here whether you consider the team a group or a bunch of individuals tends to be different for different dialects and contexts. However, there are no dialects or context where "were" is appropriate for "period."

BTW, with regards to "data/dataum" and similarly "die/dice" this is a change in language over time. Datum and die have become rarely used and are dying out, so that the putatively plural forms have become uncountable nouns in common parlance. Not everyone will agree with this assessment, it is contextually dependent, and in some circumstances the difference is still adhered to. However, I think many people would agree that that is the direction the language is going with these words, notwithstanding the argument as to how far they have gone or how fast they are going.

Wiktionary on data and Wiktionary on dice list both as uncountable as one meaning, though the plural meaning is also indicated.


Because you have a singular period as the subject, the verb should be singular:

"Our period of greatest prosperity was those eleven years when Thatcher was in office."

  • What about acceptability in speech and writing ?
    – Centaurus
    Commented Oct 27, 2014 at 23:54
  • 1
    I would use the singular........If you are called to task, you can always justify your choice. Commented Oct 28, 2014 at 0:04
  • I mean, what about the level of acceptability in speech and in writing for the plural verb?
    – Centaurus
    Commented Oct 28, 2014 at 0:13
  • 1
    If you made the error, many people would not even notice. Commented Oct 28, 2014 at 0:41

"Period" binds the eleven years together into a single collection. There's no plural any more when you come to the verb. Use "was."
What is clearly ungrammatical is unacceptable in writing and jarring in speech. It can suggest one hasn't bothered to rephrase for clarity.

If the plural is to be stressed, rephrase accordingly.


Not the answer you're looking for? Browse other questions tagged or ask your own question.