It is a very simple word but I am quite confused when I write formal documents. I do not know exactly when to use the of rather than 's. For example:

The value of the mean or The mean's value.

The domains of statistics or The statistics' domains.

The example of data or data's example.

I have searched on Google. Both cases seem widely used on many websites, so I do not know which one is well received by native speakers. Are there guidelines for choosing one over the other?

  • 2
    The general pattern is to use the suffix -'s for possessors that animate, including humans, and to use a prepositional phrase with of for inanimate possessors. Thus, the leg of the table but the horse's leg. There are many exceptions and idioms, however. Jun 12, 2013 at 19:29
  • 2
    See for instance the excellent answers on this closed question: english.stackexchange.com/questions/52104/…
    – Kit Z. Fox
    Jun 12, 2013 at 19:32
  • @JohnLawler So, the data's example is the false sentence. Right?
    – lvarayut
    Jun 12, 2013 at 19:46
  • Right. None of the abstract terms you used should have the suffix; this is especially true for metaphors, like head/foot/leg of the table. Jun 12, 2013 at 20:30

1 Answer 1


My English professor told me that we use of when we are talking about something that is part of or related to another thing. For example, ceiling of my room or subject of the lecture. But 's is used when we are speaking about the ownership relationships and usually related to a person. For example Ali's car or students' room.

But according to my researches, we use of to indicate that one thing is either related to or about something else. On the other hand we use 's to show that two or more things are part of or under the ownership of each other in some ways.

  • 3
    There are exceptions, though: one might easily say "That car's headlamp is broken."
    – Andrew Leach
    Jun 13, 2013 at 10:05

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