I used to know this 25-cent word, and I have forgotten it. It describes a phenomenon where common descriptive statistics like mean and variance misrepresent the individuals or maybe the phenomenon itself. (I don't know because I can't look it up!) I believe it begins with an e, probably an en- or eu-. Does it sound familiar to anyone?

  • $\begingroup$ Could be any number of things (bias? insufficiency? inefficiency?). It might help if you gave more context, at present this is probably too broad (too many possible answers) $\endgroup$
    – Glen_b
    Commented Jul 3, 2018 at 2:38
  • $\begingroup$ Unrepresentative or non-representative perhaps? $\endgroup$
    – Jim
    Commented Jul 3, 2018 at 9:38
  • $\begingroup$ Thanks for trying; it's more obscure than bias and the like. Encastic, euthentical, endostatic, something like that. "Children's classroom learning should not be reduced to test scores because children's individual educational experiences are . . . . eunomical . . . . or something." Looking for this one single specific word, not any word that describes this situation. $\endgroup$
    – J Kelly
    Commented Jul 3, 2018 at 15:21
  • $\begingroup$ Could it be Exogenous? en.wikipedia.org/wiki/Exogeny $\endgroup$
    – RLave
    Commented Jul 4, 2018 at 13:55

2 Answers 2


The word I'd been driving myself crazy to recall was "ergodic" -- "the ensemble average equals the time average" -- with the concept I was trying to research being "nonergodic" meaning a phenomenon dependent on its history.

  • 4
    $\begingroup$ Ergodicity is one kind of good behaviour. If anything, it makes statistical treatment easier, and not more difficult. $\endgroup$
    – Nick Cox
    Commented Jul 4, 2018 at 18:40
  • 1
    $\begingroup$ Right, @NickCox, nonergodic was the term I ultimately needed. $\endgroup$
    – J Kelly
    Commented Aug 19, 2018 at 18:42

Based on the sound of the word, maybe idiosyncratic? If there is idiosyncratic error, then estimating summary statistics just in a cross-section would not be meaningful.


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