When means and standard deviations are an incomplete summary of a continuous variable: problems, solutions, and utilising the reference ranges to check normality

Dan J. Green; Michael J. Campbell; Eirini Koutoumanou

doi:10.1136/bmjmed-2025-001796

When means and standard deviations are an incomplete summary of a continuous variable: problems, solutions, and utilising the reference ranges to check normality

Dan J. Green
, Michael J. Campbell
, Eirini Koutoumanou

Research output: Contribution to journal › Article › peer-review

Abstract

The mean and standard deviation are commonly used to summarise continuous data, often without regard for the distribution of the data. For data in a non-normal distribution, the median and interquartile interval are often more appropriate. This article outlines circumstances where the mean and standard deviation alone are insufficient summary variables, and provides a simple appraisal
method for reviewers without the raw data.

Original language	English
Article number	e001796
Number of pages	5
Journal	BMJ Medicine
Volume	5
Issue number	1
Early online date	4 Feb 2026
DOIs	https://doi.org/10.1136/bmjmed-2025-001796
Publication status	Published - 4 Feb 2026

Bibliographical note

This is an open access article distributed in accordance with the Creative Commons Attribution Non Commercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works
on different terms, provided the original work is properly cited, appropriate credit is given, any changes made indicated, and the use
is non- commercial. See: https://creativecommons.org/licenses/by-nc/4.0/

Access to Document

10.1136/bmjmed-2025-001796Licence: CC BY-NC 4.0

DJ Green et al_When means and standard deviations are an incomplete summary of a continuous variable
This is an open access article distributed in accordance with the Creative Commons Attribution Non Commercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited, appropriate credit is given, any changes made indicated, and the use is non- commercial. See: https://creativecommons.org/licenses/by-nc/4.0/
Final published version, 821 KBLicence: CC BY-NC 4.0

Cite this

@article{da9d96db635047c7a0671f06c3bb30c2,

title = "When means and standard deviations are an incomplete summary of a continuous variable: problems, solutions, and utilising the reference ranges to check normality",

abstract = "The mean and standard deviation are commonly used to summarise continuous data, often without regard for the distribution of the data. For data in a non-normal distribution, the median and interquartile interval are often more appropriate. This article outlines circumstances where the mean and standard deviation alone are insufficient summary variables, and provides a simple appraisal method for reviewers without the raw data.",

author = "Green, \{Dan J.\} and Campbell, \{Michael J.\} and Eirini Koutoumanou",

note = "This is an open access article distributed in accordance with the Creative Commons Attribution Non Commercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited, appropriate credit is given, any changes made indicated, and the use is non- commercial. See: https://creativecommons.org/licenses/by-nc/4.0/",

year = "2026",

month = feb,

day = "4",

doi = "10.1136/bmjmed-2025-001796",

language = "English",

volume = "5",

number = "1",

}

TY - JOUR

T1 - When means and standard deviations are an incomplete summary of a continuous variable: problems, solutions, and utilising the reference ranges to check normality

AU - Green, Dan J.

AU - Campbell, Michael J.

AU - Koutoumanou, Eirini

N1 - This is an open access article distributed in accordance with the Creative Commons Attribution Non Commercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited, appropriate credit is given, any changes made indicated, and the use is non- commercial. See: https://creativecommons.org/licenses/by-nc/4.0/

PY - 2026/2/4

Y1 - 2026/2/4

N2 - The mean and standard deviation are commonly used to summarise continuous data, often without regard for the distribution of the data. For data in a non-normal distribution, the median and interquartile interval are often more appropriate. This article outlines circumstances where the mean and standard deviation alone are insufficient summary variables, and provides a simple appraisal method for reviewers without the raw data.

AB - The mean and standard deviation are commonly used to summarise continuous data, often without regard for the distribution of the data. For data in a non-normal distribution, the median and interquartile interval are often more appropriate. This article outlines circumstances where the mean and standard deviation alone are insufficient summary variables, and provides a simple appraisal method for reviewers without the raw data.

UR - https://bmjmedicine.bmj.com/content/5/1/e001796

U2 - 10.1136/bmjmed-2025-001796

DO - 10.1136/bmjmed-2025-001796

M3 - Article

VL - 5

JO - BMJ Medicine

JF - BMJ Medicine

IS - 1

M1 - e001796

ER -

When means and standard deviations are an incomplete summary of a continuous variable: problems, solutions, and utilising the reference ranges to check normality

Abstract

Bibliographical note

Access to Document

Other files and links

Fingerprint

Cite this