BMJ  2003;327:557-560 (6 September), doi:10.1136/bmj.327.7414.557

Education and debate

Measuring inconsistency in meta-analyses

¹ MRC Biostatistics Unit, Institute of Public Health, Cambridge CB2 2SR, ² Cancer Research UK/NHS Centre for Statistics in Medicine, Institute of Health Sciences, Oxford OX3 7LF

Cochrane Reviews have recently started including the quantity I² to help readers assess the consistency of the results of studies in meta-analyses. What does this new quantity mean, and why is assessment of heterogeneity so important to clinical practice?

Systematic reviews and meta-analyses can provide convincing and reliable evidence relevant to many aspects of medicine and health care.¹ Their value is especially clear when the results of the studies they include show clinically important effects of similar magnitude. However, the conclusions are less clear when the included studies have differing results. In an attempt to establish whether studies are consistent, reports of meta-analyses commonly present a statistical test of heterogeneity. The test seeks to determine whether there are genuine differences underlying the results of the studies (heterogeneity), or whether the variation in findings is compatible with chance alone (homogeneity). However, the test is susceptible to the number of trials included in the meta-analysis. We have developed a new quantity, I², which we believe gives a better measure of the consistency between trials in a meta-analysis.

Assessment of the consistency of effects across studies is an essential part of . . . [Full text of this article]

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• Sakzewski, L., Ziviani, J., Boyd, R. (2009). Systematic Review and Meta-analysis of Therapeutic Management of Upper-Limb Dysfunction in Children With Congenital Hemiplegia. Pediatrics 123: e1111-e1122 [Abstract] [Full text]  
• Dentali, F., Squizzato, A., Brivio, L., Appio, L., Campiotti, L., Crowther, M., Grandi, A. M., Ageno, W. (2009). JAK2V617F mutation for the early diagnosis of Ph- myeloproliferative neoplasms in patients with venous thromboembolism: a meta-analysis. Blood 113: 5617-5623 [Abstract] [Full text]  
• Tonelli, M., Hemmelgarn, B., Reiman, T., Manns, B., Reaume, M. N., Lloyd, A., Wiebe, N., Klarenbach, S. (2009). Benefits and harms of erythropoiesis-stimulating agents for anemia related to cancer: a meta-analysis. CMAJ 180: E62-E71 [Abstract] [Full text]  
• Burns, K. E A, Adhikari, N. K J, Keenan, S. P, Meade, M. (2009). Use of non-invasive ventilation to wean critically ill adults off invasive ventilation: meta-analysis and systematic review. BMJ 338: b1574-b1574 [Abstract] [Full text]  
• Kodama, S., Saito, K., Tanaka, S., Maki, M., Yachi, Y., Asumi, M., Sugawara, A., Totsuka, K., Shimano, H., Ohashi, Y., Yamada, N., Sone, H. (2009). Cardiorespiratory Fitness as a Quantitative Predictor of All-Cause Mortality and Cardiovascular Events in Healthy Men and Women: A Meta-analysis. JAMA 301: 2024-2035 [Abstract] [Full text]  
• Scott, L. J., Muglia, P., Kong, X. Q., Guan, W., Flickinger, M., Upmanyu, R., Tozzi, F., Li, J. Z., Burmeister, M., Absher, D., Thompson, R. C., Francks, C., Meng, F., Antoniades, A., Southwick, A. M., Schatzberg, A. F., Bunney, W. E., Barchas, J. D., Jones, E. G., Day, R., Matthews, K., McGuffin, P., Strauss, J. S., Kennedy, J. L., Middleton, L., Roses, A. D., Watson, S. J., Vincent, J. B., Myers, R. M., Farmer, A. E., Akil, H., Burns, D. K., Boehnke, M. (2009). Genome-wide association and meta-analysis of bipolar disorder in individuals of European ancestry. Proc. Natl. Acad. Sci. USA 106: 7501-7506 [Abstract] [Full text]  
• Mazziotti, G., Floriani, I., Bonadonna, S., Torri, V., Chanson, P., Giustina, A. (2009). Effects of Somatostatin Analogs on Glucose Homeostasis: A Metaanalysis of Acromegaly Studies. J. Clin. Endocrinol. Metab. 94: 1500-1508 [Abstract] [Full text]  
• Hammerli, K., Znoj, H., Barth, J. (2009). The efficacy of psychological interventions for infertile patients: a meta-analysis examining mental health and pregnancy rate. Hum Reprod Update 15: 279-295 [Abstract] [Full text]  
• Toulis, K.A., Goulis, D.G., Farmakiotis, D., Georgopoulos, N.A., Katsikis, I., Tarlatzis, B.C., Papadimas, I., Panidis, D. (2009). Adiponectin levels in women with polycystic ovary syndrome: a systematic review and a meta-analysis. Hum Reprod Update 15: 297-307 [Abstract] [Full text]  

Rapid Responses:

Read all Rapid Responses

I2 Is Subject to the Same Statistical Power Problems as Cochran's Q

Tania Huedo-Medina, et al.
bmj.com, 4 Jan 2007 [Full text]

A better method of dealing with inconsistency in meta-analyses

Suhail Doi
bmj.com, 4 Jan 2008 [Full text]