IJE Advance Access originally published online on August 27, 2004
International Journal of Epidemiology 2005 34(1):215-220; doi:10.1093/ije/dyh299
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
IJE vol.34 no.1 © International Epidemiological Association 2004; all rights reserved.
Education |
Regression to the mean: what it is and how to deal with it
1 School of Population Health, The University of Queensland, Herston, Brisbane QLD 4006, Australia
Correspondence: Adrian Barnett, School of Population Health, The University of Queensland, Brisbane QLD 4006, Australia. E-mail: a.barnett{at}uq.edu.au
Background Regression to the mean (RTM) is a statistical phenomenon that can make natural variation in repeated data look like real change. It happens when unusually large or small measurements tend to be followed by measurements that are closer to the mean.
Methods We give some examples of the phenomenon, and discuss methods to overcome it at the design and analysis stages of a study.
Results The effect of RTM in a sample becomes more noticeable with increasing measurement error and when follow-up measurements are only examined on a sub-sample selected using a baseline value.
Conclusions RTM is a ubiquitous phenomenon in repeated data and should always be considered as a possible cause of an observed change. Its effect can be alleviated through better study design and use of suitable statistical methods.
Keywords Regression to the mean, repeated measures, intervention, clinical trials, observational studies, longitudinal studies, statistics, epidemiological research design
Accepted 1 July 2004
CiteULike 
Connotea 
Del.icio.us What's this?
This article has been cited by other articles:
|
|
 |
|
  J. A.C. Delaney, B. E. Oddson, H. Kramer, S. Shea, B. M. Psaty, and R. L. McClelland Baseline Depressive Symptoms Are Not Associated With Clinically Important Levels of Incident Hypertension During Two Years of Follow-Up: The Multi-Ethnic Study of Atherosclerosis Hypertension, February 1, 2010; 55(2): 408 - 414. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 S. Senthilkumar, B. Basso, A. N. Kravchenko, and G. P. Robertson Contemporary Evidence of Soil Carbon Loss in the U.S. Corn Belt Soil Sci. Soc. Am. J., October 21, 2009; 73(6): 2078 - 2086. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 T Agoritsas, A Lubbeke, L Schiesari, and T V Perneger Assessment of patients' tendency to give a positive or negative rating to healthcare Qual. Saf. Health Care, October 1, 2009; 18(5): 374 - 379. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 W. C. Hawkes, Z. Alkan, and K. Wong Selenium Supplementation Does Not Affect Testicular Selenium Status or Semen Quality in North American Men J Androl, September 1, 2009; 30(5): 525 - 533. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 A Dugravot, A Gueguen, M Kivimaki, J Vahtera, M Shipley, M G Marmot, and A Singh-Manoux Socioeconomic position and cognitive decline using data from two waves: what is the role of the wave 1 cognitive measure? J Epidemiol Community Health, August 1, 2009; 63(8): 675 - 680. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 D. A. I. Groffen, H. Bosma, M. van den Akker, G. I. J. M. Kempen, and J. Th. M. van Eijk Personality and health as predictors of income decrease in old age: Findings from the longitudinal SMILE study Eur J Public Health, August 1, 2009; 19(4): 418 - 423. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 A. S. Chan, M.-c. Cheung, W. J. Tsui, S. L. Sze, and D. Shi Dejian Mind-Body Intervention on Depressive Mood of Community-Dwelling Adults: A Randomized Controlled Trial Evid. Based Complement. Altern. Med., May 27, 2009; (2009) nep043v1. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 P. S. Parfrey, M. Lauve, D. Latremouille-Viau, and P. Lefebvre Erythropoietin Therapy and Left Ventricular Mass Index in CKD and ESRD Patients: A Meta-Analysis Clin. J. Am. Soc. Nephrol., April 1, 2009; 4(4): 755 - 762. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 O. N. Keene, B. Celli, J. A. Anderson, G. T. Ferguson, C. R. Jenkins, P. W. Jones, J. Vestbo, K. Knobil, J. C. Yates, and P. M. A. Calverley Lung function decline in COPD trials Eur. Respir. J., March 1, 2009; 33(3): 708 - 709. [Full Text] [PDF]
|
|
|
|
 |
|
 M. Onslow, M. Jones, S. O'Brian, R. Menzies, and A. Packman Defining, Identifying, and Evaluating Clinical Trials of Stuttering Treatments: A Tutorial for Clinicians Am J Speech Lang Pathol, November 1, 2008; 17(4): 401 - 415. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 W. S. Weintraub, J. A. Spertus, P. Kolm, D. J. Maron, Z. Zhang, C. Jurkovitz, W. Zhang, P. M. Hartigan, C. Lewis, E. Veledar, et al. Effect of PCI on Quality of Life in Patients with Stable Coronary Disease N. Engl. J. Med., August 14, 2008; 359(7): 677 - 687. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 P Smith and D Beaton Measuring change in psychosocial working conditions: methodological issues to consider when data are collected at baseline and one follow-up time point Occup. Environ. Med., April 1, 2008; 65(4): 288 - 296. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 A. A. Wong, P. J. Schluter, R. D. Henderson, J. D. O'Sullivan, and S. J. Read Natural history of blood glucose within the first 48 hours after ischemic stroke Neurology, March 25, 2008; 70(13): 1036 - 1041. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 E. A.M. Gale, S. D. Beattie, J. Hu, V. Koivisto, and M. H. Tan Recruitment to a Clinical Trial Improves Glycemic Control in Patients With Diabetes Diabetes Care, December 1, 2007; 30(12): 2989 - 2992. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
S. Kirsh, S. Watts, K. Pascuzzi, M. E. O'Day, D. Davidson, G. Strauss, E. O Kern, and D. C Aron Shared medical appointments based on the chronic care model: a quality improvement project to address the challenges of patients with diabetes with high cardiovascular risk Qual. Saf. Health Care, October 1, 2007; 16(5): 349 - 353. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 M. C. Greenwood, J. Rathi, A. J. Hakim, D. L. Scott, and D. V. Doyle Regression to the mean using the disease activity score in eligibility and response criteria for prescribing TNF-{alpha} inhibitors in adults with rheumatoid arthritis Rheumatology, July 1, 2007; 46(7): 1165 - 1167. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 F. Turnbull and A. Patel Acupuncture for Blood Pressure Lowering: Needling the Truth Circulation, June 19, 2007; 115(24): 3048 - 3049. [Full Text] [PDF]
|
|
|
|
 |
|
 P. H. Quanjer, J. P. Schouten, M. R. Miller, and G. Ruppel Avoiding Bias in the Annualized Rate of Change of FEV1 Am. J. Respir. Crit. Care Med., February 1, 2007; 175(3): 291 - 292. [Full Text] [PDF]
|
|
|
|
 |
|
 M. A. Mendez, B. M. Popkin, P. Jakszyn, A. Berenguer, M. J. Tormo, M. J. Sanchez, J. R. Quiros, G. Pera, C. Navarro, C. Martinez, et al. Adherence to a Mediterranean Diet Is Associated with Reduced 3-Year Incidence of Obesity J. Nutr., November 1, 2006; 136(11): 2934 - 2938. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 G. S. Liptak, L. P. Shone, P. Auinger, A. W. Dick, S. A. Ryan, and P. G. Szilagyi Short-term Persistence of High Health Care Costs in a Nationally Representative Sample of Children Pediatrics, October 1, 2006; 118(4): e1001 - e1009. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 E. Hendershot, A. Pappo, D. Malkin, and L. Sung Tumor Necrosis in Pediatric Osteosarcoma: Impact of Modern Therapies Journal of Pediatric Oncology Nursing, July 1, 2006; 23(4): 176 - 181. [Abstract] [PDF]
|
|
|
|
 |
|
 S. Al-Ruzzeh, S. George, M. Bustami, J. Wray, C. Ilsley, T. Athanasiou, and M. Amrani Effect of off-pump coronary artery bypass surgery on clinical, angiographic, neurocognitive, and quality of life outcomes: randomised controlled trial BMJ, June 10, 2006; 332(7554): 1365. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 J. R. Goffin and J. R. Talavera Overstated Conclusions of a Pooled Analysis of Bevacizumab in Colon Cancer J. Clin. Oncol., January 20, 2006; 24(3): 528 - 529. [Full Text] [PDF]
|
|
|
|
 |
|
 G. D. Smith Epidemiological Freudianism Int. J. Epidemiol., February 1, 2005; 34(1): 1 - 2. [Full Text] [PDF]
|
|