Home IPS Feedback Subscribe Top cited articles Login Users Online : 1795

 »  Similar in PUBMED »  Search Pubmed forJaykaran »  Search in Google Scholar for Jaykaran »  Article in PDF (131 KB) »  Citation Manager »  Access Statistics »  Reader Comments »  Email Alert * »  Add to My List * * Registration required (free)

 »  References

CORRESPONDENCE
Year : 2010  |  Volume : 42  |  Issue : 5  |  Page : 329

"Mean ± SEM" or "Mean (SD)"?

Department of Pharmacology, Government Medical College, Surat, India

 Date of Web Publication 17-Sep-2010

Jaykaran
Department of Pharmacology, Government Medical College, Surat
India

Source of Support: None, Conflict of Interest: None

DOI: 10.4103/0253-7613.70402

 How to cite this article:Jaykaran. "Mean ± SEM" or "Mean (SD)"?. Indian J Pharmacol 2010;42:329

 How to cite this URL:Jaykaran. "Mean ± SEM" or "Mean (SD)"?. Indian J Pharmacol [serial online] 2010 [cited 2020 May 25];42:329. Available from: http://www.ijp-online.com/text.asp?2010/42/5/329/70402

Sir,

Use of descriptive statistics is very common in articles published in various medical journals. For the ratio and interval data following the normal distribution, the most common descriptive statistics is mean and standard deviation (SD) and for data not following the normal distribution, it is median and range. It is, however, observed in various medical journals that mean and standard error of mean (SEM) are used to describe the variability within the sample. [1] We, therefore, need to understand the difference between SEM and SD.

The SEM is a measure of precision for an estimated population mean. SD is a measure of data variability around mean of a sample of population. Unlike SD, SEM is not a descriptive statistics and should not be used as such. However, many authors incorrectly use the SEM as a descriptive statistics to summarize the variability in their data because it is less than the SD, implying incorrectly that their measurements are more precise. The SEM is correctly used only to indicate the precision of estimated mean of population. Even then however, a 95% confidence interval should be preferred. [1],[2] Further, while reporting mean and SD, instead of writing "mean ± SD" the better way of representation would be "mean (SD)" as it will decrease the chance of confusion with confidence interval. [2]

 » References

 1 Nagele P. Misuse of standard error of the mean (SEM) when reporting variability of a sample. A critical evaluation of four anaesthesia journals. Br J Anaesth 2003;90:514-6.    [PUBMED]  [FULLTEXT] 2 Tom L. Twenty statistical error even YOU can find in biomedical research articles. Croat Med J 2004;45:361-70.

 This article has been cited by 1 Inappropriate use of standard error of the mean when reporting variability of study samples: A critical evaluation of four selected journals of obstetrics and gynecology Wen-Ru Ko,Wei-Te Hung,Hui-Chin Chang,Long-Yau Lin Taiwanese Journal of Obstetrics and Gynecology. 2014; 53(1): 26 [Pubmed] | [DOI] 2 Mean (Standard Deviation) or Mean (Standard Error of Mean): Time to Ponder Pankaj Kumar Garg,Debajyoti Mohanty World Journal of Surgery. 2013; 37(4): 932 [Pubmed] | [DOI] 3 Suggested statistical reporting guidelines for clinical trials data Charan, J., Saxena, D. Indian Journal of Psychological Medicine. 2012; 34(1): 25-29 [Pubmed]

 Previous article Next article