Most scientific papers present data using mean (95%CI lower bound, 95%CI upper bound) but I have not seen mean ± 95% CI (upper bound - mean). Can I use the latter to present my results?


mean = 1.0
CIlb = 0.8
CIub = 1.2

Can I present the result as 1 ± 0.2 (mean ± 95%CI)or must I present as 1.0 (0.8, 1.2)?

  • $\begingroup$ Can you give a concrete example? $\endgroup$ Commented Jul 6, 2023 at 14:20
  • $\begingroup$ yes, I just added one $\endgroup$
    – Elizabeth
    Commented Jul 6, 2023 at 14:20
  • 3
    $\begingroup$ You can do that... if the CI is symmetric. $\endgroup$ Commented Jul 6, 2023 at 14:21
  • $\begingroup$ @user2974951 How is the poor reader supposed to understand either expression, exactly? There appear to be multiple reasonable interpretations of them, and "mean ± 95%CI," which explicitly appears to sum a number with an interval about that number is either nonsensical or wrong. $\endgroup$
    – whuber
    Commented Jul 6, 2023 at 17:41
  • $\begingroup$ I suspect that credible intervals would serve much better for the kind of result summary that you have in mind. $\endgroup$
    – Durden
    Commented Jul 7, 2023 at 0:14

1 Answer 1


Not all CIs are symmetrical, so the tradition is to report a confidence interval as an interval ("from LL to UL", or "LL,UL")

In your example, the CI is symmetrical so the plus/minus nomenclature is not ambiguous and is easy to understand. But it is not standard. You describe it as "mean ± 95% CI" but you really mean "mean ± margin of error", which is a better way to describe your syntax.


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