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?

The first 150 words of the full text of this article appear below.

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.

Need for consistency

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

Testing for heterogeneity

Quantifying heterogeneity: a better approach

Examples of values of I²

Further applications of I²

Methodological subgroups
Heterogeneity related to choice of effect measure
Clinically important subgroups

How much is too much heterogeneity?

CiteULike    Complore    Connotea    Del.icio.us    Digg    Reddit    Technorati    What's this?

This article has been cited by other articles:

• ter Riet, G. MD PhD, Cnossen, J. S. MD, van der Post, J. A.M. MD PhD, Mol, B. W. MD PhD, Morris, R. K. MD, Khan, K. S. MD (2008). Use of Doppler ultrasonography to predict pre-eclampsia. CMAJ 179: 53-54 [Full text]  
• AlBuhairan, B., Hind, D., Hutchinson, A. (2008). Antibiotic prophylaxis for wound infections in total joint arthroplasty: A SYSTEMATIC REVIEW. J Bone Joint Surg Br 90-B: 915-919 [Abstract] [Full text]  
• Capon, F., Bijlmakers, M.-J., Wolf, N., Quaranta, M., Huffmeier, U., Allen, M., Timms, K., Abkevich, V., Gutin, A., Smith, R., Warren, R. B., Young, H. S., Worthington, J., Burden, A. D., Griffiths, C. E.M., Hayday, A., Nestle, F. O., Reis, A., Lanchbury, J., Barker, J. N., Trembath, R. C. (2008). Identification of ZNF313/RNF114 as a novel psoriasis susceptibility gene. Hum Mol Genet 17: 1938-1945 [Abstract] [Full text]  
• Walther, A, Houlston, R, Tomlinson, I (2008). Association between chromosomal instability and prognosis in colorectal cancer: a meta-analysis. Gut 57: 941-950 [Abstract] [Full text]  
• Duesing, K., Fatemifar, G., Charpentier, G., Marre, M., Tichet, J., Hercberg, S., Balkau, B., Froguel, P., Gibson, F. (2008). Evaluation of the Association of IGF2BP2 Variants With Type 2 Diabetes in French Caucasians. Diabetes 57: 1992-1996 [Abstract] [Full text]  
• Akl, E. A., Terrenato, I., Barba, M., Sperati, F., Sempos, E. V., Muti, P., Cook, D. J., Schunemann, H. J. (2008). Low-Molecular-Weight Heparin vs Unfractionated Heparin for Perioperative Thromboprophylaxis in Patients With Cancer: A Systematic Review and Meta-analysis. Arch Intern Med 168: 1261-1269 [Abstract] [Full text]  
• Ioannidis, J. P A, Patsopoulos, N. A, Rothstein, H. R (2008). Reasons or excuses for avoiding meta-analysis in forest plots. BMJ 336: 1413-1415 [Full text]  
• Thompson, A., Di Angelantonio, E., Sarwar, N., Erqou, S., Saleheen, D., Dullaart, R. P. F., Keavney, B., Ye, Z., Danesh, J. (2008). Association of Cholesteryl Ester Transfer Protein Genotypes With CETP Mass and Activity, Lipid Levels, and Coronary Risk. JAMA 299: 2777-2788 [Abstract] [Full text]  
• Jafri, N. S., Hornung, C. A., Howden, C. W. (2008). Meta-analysis: Sequential Therapy Appears Superior to Standard Therapy for Helicobacter pylori Infection in Patients Naive to Treatment. ANN INTERN MED 148: 923-931 [Abstract] [Full text]  
• Auer, R., Gaume, J., Rodondi, N., Cornuz, J., Ghali, W. A. (2008). Efficacy of In-Hospital Multidimensional Interventions of Secondary Prevention After Acute Coronary Syndrome: A Systematic Review and Meta-Analysis. Circulation 117: 3109-3117 [Abstract] [Full text]  
• Colman, I., Friedman, B. W, Brown, M. D, Innes, G. D, Grafstein, E., Roberts, T. E, Rowe, B. H (2008). Parenteral dexamethasone for acute severe migraine headache: meta-analysis of randomised controlled trials for preventing recurrence. BMJ 336: 1359-1361 [Abstract] [Full text]  
• Yousef, F., Cardwell, C., Cantwell, M. M., Galway, K., Johnston, B. T., Murray, L. (2008). The Incidence of Esophageal Cancer and High-Grade Dysplasia in Barrett's Esophagus: A Systematic Review and Meta-Analysis. Am J Epidemiol 0: kwn121v1-kwn121 [Full text]  
• Ochs, N., Auer, R., Bauer, D. C., Nanchen, D., Gussekloo, J., Cornuz, J., Rodondi, N. (2008). Meta-analysis: Subclinical Thyroid Dysfunction and the Risk for Coronary Heart Disease and Mortality. ANN INTERN MED 148: 832-845 [Abstract] [Full text]  
• Higgins, J. P., White, I. R, Wood, A. M (2008). Imputation methods for missing outcome data in meta-analysis of clinical trials. Clin Trials 5: 225-239 [Abstract]  
• Salanti, G., Higgins, J. P., Ades, A., Ioannidis, J. P. (2008). Evaluation of networks of randomized trials. Stat Methods Med Res 17: 279-301 [Abstract]  
• Chong, E. W-T., Kreis, A. J., Wong, T. Y., Simpson, J. A., Guymer, R. H. (2008). Dietary {omega}-3 Fatty Acid and Fish Intake in the Primary Prevention of Age-Related Macular Degeneration: A Systematic Review and Meta-analysis. Arch Ophthalmol 126: 826-833 [Abstract] [Full text]  
• Duffield, T. F., Rabiee, A. R., Lean, I. J. (2008). A Meta-Analysis of the Impact of Monensin in Lactating Dairy Cattle. Part 3. Health and Reproduction. J DAIRY SCI 91: 2328-2341 [Abstract] [Full text]  
• Lau, J T F, Choi, K C, Tsui, H Y, Zhang, L, Zhang, J, Lan, Y, Zhang, Y, Wang, N, Cheng, F, Gu, J (2008). Changes in HIV-related behaviours over time and associations with rates of HIV-related services coverage among female sex workers in Sichuan, China. Sex. Transm. Infect. 84: 212-216 [Abstract] [Full text]  
• Dahabreh, I. J., Linardou, H., Siannis, F., Fountzilas, G., Murray, S. (2008). Trastuzumab in the Adjuvant Treatment of Early-Stage Breast Cancer: A Systematic Review and Meta-Analysis of Randomized Controlled Trials. The Oncologist 13: 620-630 [Abstract] [Full text]  
• Canonico, M., Plu-Bureau, G., Lowe, G. D O, Scarabin, P.-Y. (2008). Hormone replacement therapy and risk of venous thromboembolism in postmenopausal women: systematic review and meta-analysis. BMJ 336: 1227-1231 [Abstract] [Full text]  
• Natanson, C., Kern, S. J., Lurie, P., Banks, S. M., Wolfe, S. M. (2008). Cell-Free Hemoglobin-Based Blood Substitutes and Risk of Myocardial Infarction and Death: A Meta-analysis. JAMA 299: 2304-2312 [Abstract] [Full text]  
• Meta-Analysis Research Group in Echocardiography (, (2008). Independent Prognostic Importance of a Restrictive Left Ventricular Filling Pattern After Myocardial Infarction: An Individual Patient Meta-Analysis: Meta-Analysis Research Group in Echocardiography Acute Myocardial Infarction. Circulation 117: 2591-2598 [Abstract] [Full text]  
• Chapman, K., Takahashi, A., Meulenbelt, I., Watson, C., Rodriguez-Lopez, J., Egli, R., Tsezou, A., Malizos, K. N., Kloppenburg, M., Shi, D., Southam, L., van der Breggen, R., Donn, R., Qin, J., Doherty, M., Slagboom, P. E., Wallis, G., Kamatani, N., Jiang, Q., Gonzalez, A., Loughlin, J., Ikegawa, S. (2008). A meta-analysis of European and Asian cohorts reveals a global role of a functional SNP in the 5' UTR of GDF5 with osteoarthritis susceptibility. Hum Mol Genet 17: 1497-1504 [Abstract] [Full text]  
• Krebs, E. E., Gaynes, B. N., Gartlehner, G., Hansen, R. A., Thieda, P., Morgan, L. C., DeVeaugh-Geiss, A., Lohr, K. N. (2008). Treating the Physical Symptoms of Depression With Second-Generation Antidepressants: A Systematic Review and Metaanalysis. Psychosomatics 49: 191-198 [Abstract] [Full text]  
• Baker, W. L., White, C. M., Coleman, C. I. (2008). Effect of Nonergot Dopamine Agonists on Symptoms of Restless Legs Syndrome. Ann Fam Med 6: 253-262 [Abstract] [Full text]  
• Rodrigo, G. J., Nannini, L. J., Rodriguez-Roisin, R. (2008). Safety of Long-Acting {beta}-Agonists in Stable COPD: A Systematic Review. Chest 133: 1079-1087 [Abstract] [Full text]  
• Elamin, M. B., Murad, M. H., Mullan, R., Erickson, D., Harris, K., Nadeem, S., Ennis, R., Erwin, P. J., Montori, V. M. (2008). Accuracy of Diagnostic Tests for Cushing's Syndrome: A Systematic Review and Metaanalyses. J. Clin. Endocrinol. Metab. 93: 1553-1562 [Abstract] [Full text]  
• Shah, N. R., Jones, J. B., Aperi, J., Shemtov, R., Karne, A., Borenstein, J. (2008). Selective Serotonin Reuptake Inhibitors for Premenstrual Syndrome and Premenstrual Dysphoric Disorder: A Meta-Analysis. Obstet Gynecol 111: 1175-1182 [Abstract] [Full text]  
• Testa, L., van Gaal, W.J., Biondi-Zoccai, G.G.L., Abbate, A., Agostoni, P., Bhindi, R., Banning, A.P. (2008). Repeat thrombolysis or conservative therapy vs. rescue percutaneous coronary intervention for failed thrombolysis: systematic review and meta-analysis. QJM 101: 387-395 [Abstract] [Full text]  
• Vercammen, M.J., Verloes, A., Van de Velde, H., Haentjens, P. (2008). Accuracy of soluble human leukocyte antigen-G for predicting pregnancy among women undergoing infertility treatment: meta-analysis. Hum Reprod Update 14: 209-218 [Abstract] [Full text]  
• Freathy, R. M., Timpson, N. J., Lawlor, D. A., Pouta, A., Ben-Shlomo, Y., Ruokonen, A., Ebrahim, S., Shields, B., Zeggini, E., Weedon, M. N., Lindgren, C. M., Lango, H., Melzer, D., Ferrucci, L., Paolisso, G., Neville, M. J., Karpe, F., Palmer, C. N.A., Morris, A. D., Elliott, P., Jarvelin, M.-R., Davey Smith, G., McCarthy, M. I., Hattersley, A. T., Frayling, T. M. (2008). Common Variation in the FTO Gene Alters Diabetes-Related Metabolic Traits to the Extent Expected Given Its Effect on BMI. Diabetes 57: 1419-1426 [Abstract] [Full text]  
• Barbui, C., Signoretti, A., Mule, S., Boso, M., Cipriani, A. (2008). Does the Addition of a Second Antipsychotic Drug Improve Clozapine Treatment?. Schizophr Bull 0: sbn030v1-sbn030 [Abstract] [Full text]  
• Sud, S. MD, Sud, M. BSc, Friedrich, J. O. MD DPhil, Adhikari, N. K.J. MDCM MSc (2008). Effect of mechanical ventilation in the prone position on clinical outcomes in patients with acute hypoxemic respiratory failure: a systematic review and meta-analysis. CMAJ 178: 1153-1161 [Abstract] [Full text]  
• Correll, C. U., Rummel-Kluge, C., Corves, C., Kane, J. M., Leucht, S. (2008). Antipsychotic Combinations vs Monotherapy in Schizophrenia: A Meta-analysis of Randomized Controlled Trials. Schizophr Bull 0: sbn018v2-sbn018 [Abstract] [Full text]  
• Patsopoulos, N. A, Evangelou, E., Ioannidis, J. P. (2008). Sensitivity of between-study heterogeneity in meta-analysis: proposed metrics and empirical evaluation. Int J Epidemiol 0: dyn065v1-dyn065 [Abstract] [Full text]  
• Zohlnhofer, D., Dibra, A., Koppara, T., de Waha, A., Ripa, R. S., Kastrup, J., Valgimigli, M., Schomig, A., Kastrati, A. (2008). Stem Cell Mobilization by Granulocyte Colony-Stimulating Factor for Myocardial Recovery After Acute Myocardial Infarction: A Meta-Analysis. J Am Coll Cardiol 51: 1429-1437 [Abstract] [Full text]  
• Gilbody, S. DPhil, Sheldon, T. DSc, House, A. DM (2008). Screening and case-finding instruments for depression: a meta-analysis. CMAJ 178: 997-1003 [Abstract] [Full text]  
• Vescio, M F, Longo, B, Babudieri, S, Starnini, G, Carbonara, S, Rezza, G, Monarca, R (2008). Correlates of hepatitis C virus seropositivity in prison inmates: a meta-analysis. J. Epidemiol. Community Health 62: 305-313 [Abstract] [Full text]  
• Dahabreh, I. J (2008). Meta-analysis of rare events: an update and sensitivity analysis of cardiovascular events in randomized trials of rosiglitazone. Clin Trials 5: 116-120 [Abstract]  
• Bollen, A.-M., Cunha-Cruz, J., Bakko, D. W., Huang, G. J., Hujoel, P. P. (2008). The Effects of Orthodontic Therapy on Periodontal Health: A Systematic Review of Controlled Evidence. Journal of the American Dental Association 139: 413-422 [Abstract] [Full text]  
• Meilink, A., Hemmen, B., Seelen, H., Kwakkel, G. (2008). Impact of EMG-triggered neuromuscular stimulation of the wrist and finger extensors of the paretic hand after stroke: a systematic review of the literature. Clin Rehabil 22: 291-305 [Abstract]  
• Duffield, T. F., Rabiee, A. R., Lean, I. J. (2008). A Meta-Analysis of the Impact of Monensin in Lactating Dairy Cattle. Part 1. Metabolic Effects. J DAIRY SCI 91: 1334-1346 [Abstract] [Full text]  
• Duffield, T. F., Rabiee, A. R., Lean, I. J. (2008). A Meta-Analysis of the Impact of Monensin in Lactating Dairy Cattle. Part 2. Production Effects. J DAIRY SCI 91: 1347-1360 [Abstract] [Full text]  
• Blozik, E., Scherer, M. (2008). Skin Replacement Therapies for Diabetic Foot Ulcers: Systematic review and meta-analysis. Diabetes Care 31: 693-694 [Full text]  
• Garcia, A. M, Sisternas, A., Hoyos, S. P. (2008). Occupational exposure to extremely low frequency electric and magnetic fields and Alzheimer disease: a meta-analysis. Int J Epidemiol 37: 329-340 [Abstract] [Full text]  
• Carlsten, C., Sagoo, G. S., Frodsham, A. J., Burke, W., Higgins, J. P. T. (2008). Glutathione S-Transferase M1 (GSTM1) Polymorphisms and Lung Cancer: A Literature-based Systematic HuGE Review and Meta-Analysis. Am J Epidemiol 167: 759-774 [Abstract] [Full text]  
• Karageorgopoulos, D. E. MD, Giannopoulou, K. P. MD, Grammatikos, A. P. MD MSc, Dimopoulos, G. MD, Falagas, M. E. MD DSc (2008). Fluoroquinolones compared with {beta}-lactam antibiotics for the treatment of acute bacterial sinusitis: a meta-analysis of randomized controlled trials. CMAJ 178: 845-854 [Abstract] [Full text]  
• Horvath, K., Jeitler, K., Siering, U., Stich, A. K., Skipka, G., Gratzer, T. W., Siebenhofer, A. (2008). Long-term Effects of Weight-Reducing Interventions in Hypertensive Patients: Systematic Review and Meta-analysis. Arch Intern Med 168: 571-580 [Abstract] [Full text]  
• Bennet, A., Di Angelantonio, E., Erqou, S., Eiriksdottir, G., Sigurdsson, G., Woodward, M., Rumley, A., Lowe, G. D. O., Danesh, J., Gudnason, V. (2008). Lipoprotein(a) Levels and Risk of Future Coronary Heart Disease: Large-Scale Prospective Data. Arch Intern Med 168: 598-608 [Abstract] [Full text]  
• Strippoli, G. F M, Navaneethan, S. D, Johnson, D. W, Perkovic, V., Pellegrini, F., Nicolucci, A., Craig, J. C (2008). Effects of statins in patients with chronic kidney disease: meta-analysis and meta-regression of randomised controlled trials. BMJ 336: 645-651 [Abstract] [Full text]  
• van Meurs, J. B. J., Trikalinos, T. A., Ralston, S. H., Balcells, S., Brandi, M. L., Brixen, K., Kiel, D. P., Langdahl, B. L., Lips, P., Ljunggren, O., Lorenc, R., Obermayer-Pietsch, B., Ohlsson, C., Pettersson, U., Reid, D. M., Rousseau, F., Scollen, S., Van Hul, W., Agueda, L., Akesson, K., Benevolenskaya, L. I., Ferrari, S. L., Hallmans, G., Hofman, A., Husted, L. B., Kruk, M., Kaptoge, S., Karasik, D., Karlsson, M. K., Lorentzon, M., Masi, L., McGuigan, F. E. A., Mellstrom, D., Mosekilde, L., Nogues, X., Pols, H. A. P., Reeve, J., Renner, W., Rivadeneira, F., van Schoor, N. M., Weber, K., Ioannidis, J. P. A., Uitterlinden, A. G., for the GENOMOS Study, (2008). Large-Scale Analysis of Association Between LRP5 and LRP6 Variants and Osteoporosis. JAMA 299: 1277-1290 [Abstract] [Full text]  
• Wilt, T. J., MacDonald, R., Rutks, I., Shamliyan, T. A., Taylor, B. C., Kane, R. L. (2008). Systematic Review: Comparative Effectiveness and Harms of Treatments for Clinically Localized Prostate Cancer. ANN INTERN MED 148: 435-448 [Abstract] [Full text]  
• Broadbent, H. M., Peden, J. F., Lorkowski, S., Goel, A., Ongen, H., Green, F., Clarke, R., Collins, R., Franzosi, M. G., Tognoni, G., Seedorf, U., Rust, S., Eriksson, P., Hamsten, A., Farrall, M., Watkins, H., for the PROCARDIS consortium, (2008). Susceptibility to coronary artery disease and diabetes is encoded by distinct, tightly linked SNPs in the ANRIL locus on chromosome 9p. Hum Mol Genet 17: 806-814 [Abstract] [Full text]  
• Manheimer, E., Zhang, G., Udoff, L., Haramati, A., Langenberg, P., Berman, B. M, Bouter, L. M (2008). Effects of acupuncture on rates of pregnancy and live birth among women undergoing in vitro fertilisation: systematic review and meta-analysis. BMJ 336: 545-549 [Abstract] [Full text]  
• Wang, F., Chang, D., Hu, F.-l., Sui, H., Han, B., li, D.-d., Zhao, Y.-s. (2008). DNA Repair Gene XPD Polymorphisms and Cancer Risk: A Meta-analysis Based on 56 Case-Control Studies. Cancer Epidemiol. Biomarkers Prev. 17: 507-517 [Abstract] [Full text]  
• Ranucci, M., Isgro, G., Soro, G., Conti, D., De Toffol, B. (2008). Efficacy and Safety of Recombinant Activated Factor VII in Major Surgical Procedures: Systematic Review and Meta-analysis of Randomized Clinical Trials. Arch Surg 143: 296-304 [Abstract] [Full text]  
• Penagos, M., Passalacqua, G., Compalati, E., Baena-Cagnani, C. E., Orozco, S., Pedroza, A., Canonica, G. W. (2008). Metaanalysis of the Efficacy of Sublingual Immunotherapy in the Treatment of Allergic Asthma in Pediatric Patients, 3 to 18 Years of Age. Chest 133: 599-609 [Abstract] [Full text]  
• Smith, B. R., Blumstein, D. T. (2008). Fitness consequences of personality: a meta-analysis. Behav Ecol 19: 448-455 [Abstract] [Full text]  
• Cronin, P., Dwamena, B. A., Kelly, A. M., Carlos, R. C. (2008). Solitary Pulmonary Nodules: Meta-analytic Comparison of Cross-sectional Imaging Modalities for Diagnosis of Malignancy. Radiology 246: 772-782 [Abstract] [Full text]  
• Josan, K. MD, Majumdar, S. R. MD MPH, McAlister, F. A. MD MSc (2008). The efficacy and safety of intensive statin therapy: a meta-analysis of randomized trials. CMAJ 178: 576-584 [Abstract] [Full text]  
• Pannu, N., Klarenbach, S., Wiebe, N., Manns, B., Tonelli, M., for the Alberta Kidney Disease Network, (2008). Renal Replacement Therapy in Patients With Acute Renal Failure: A Systematic Review. JAMA 299: 793-805 [Abstract] [Full text]  
• Kelly, A. M., Dwamena, B., Cronin, P., Bernstein, S. J., Carlos, R. C. (2008). Meta-analysis: Effectiveness of Drugs for Preventing Contrast-Induced Nephropathy. ANN INTERN MED 148: 284-294 [Abstract] [Full text]  
• Nygren, P., Fu, R., Freeman, M., Bougatsos, C., Klebanoff, M., Guise, J.-M. (2008). Evidence on the Benefits and Harms of Screening and Treating Pregnant Women Who Are Asymptomatic for Bacterial Vaginosis: An Update Review for the U.S. Preventive Services Task Force. ANN INTERN MED 148: 220-233 [Abstract] [Full text]  
• Griffin, S.O., Oong, E., Kohn, W., Vidakovic, B., Gooch, B.F., CDC Dental Sealant Systematic Review Work Group, , Bader, J., Clarkson, J., Fontana, M.R., Meyer, D.M., Rozier, R.G., Weintraub, J.A., Zero, D.T. (2008). The Effectiveness of Sealants in Managing Caries Lesions. J. Dent. Res. 87: 169-174 [Abstract] [Full text]  
• Weischer, M., Bojesen, S. E., Ellervik, C., Tybjaerg-Hansen, A., Nordestgaard, B. G. (2008). CHEK2*1100delC Genotyping for Clinical Assessment of Breast Cancer Risk: Meta-Analyses of 26,000 Patient Cases and 27,000 Controls. JCO 26: 542-548 [Abstract] [Full text]  
• van Rijen, M. M. L., Bonten, M., Wenzel, R. P., Kluytmans, J. A. J. W. (2008). Intranasal mupirocin for reduction of Staphylococcus aureus infections in surgical patients with nasal carriage: a systematic review. J Antimicrob Chemother 61: 254-261 [Abstract] [Full text]  
• Koopman, L., Hoes, A. W., Glasziou, P. P., Appelman, C. L., Burke, P., McCormick, D. P., Damoiseaux, R. A., Le Saux, N., Rovers, M. M. (2008). Antibiotic Therapy to Prevent the Development of Asymptomatic Middle Ear Effusion in Children With Acute Otitis Media: A Meta-analysis of Individual Patient Data. Arch Otolaryngol Head Neck Surg 134: 128-132 [Abstract] [Full text]  
• Zemek, R. L., Bhogal, S. K., Ducharme, F. M. (2008). Systematic Review of Randomized Controlled Trials Examining Written Action Plans in Children: What Is the Plan?. Arch Pediatr Adolesc Med 162: 157-163 [Abstract] [Full text]  
• Hegedus, E J, Goode, A, Campbell, S, Morin, A, Tamaddoni, M, Moorman, C T III, Cook, C (2008). Physical examination tests of the shoulder: a systematic review with meta-analysis of individual tests. Br. J. Sports. Med. 42: 80-92 [Abstract] [Full text]  
• Ioannidis, J. P., Boffetta, P., Little, J., O'Brien, T. R, Uitterlinden, A. G, Vineis, P., Balding, D. J, Chokkalingam, A., Dolan, S. M, Flanders, W D., Higgins, J. P., McCarthy, M. I, McDermott, D. H, Page, G. P, Rebbeck, T. R, Seminara, D., Khoury, M. J (2008). Assessment of cumulative evidence on genetic associations: interim guidelines. Int J Epidemiol 37: 120-132 [Abstract] [Full text]  
• Barbui, C. MD, Furukawa, T. A. MD, Cipriani, A. MD (2008). Effectiveness of paroxetine in the treatment of acute major depression in adults: a systematic re-examination of published and unpublished data from randomized trials. CMAJ 178: 296-305 [Abstract] [Full text]  
• Jenkins, D. J.A. MD PhD, Josse, A. R. MSc, Beyene, J. PhD, Dorian, P. MD MSc, Burr, M. L. MD DSc (Me, LaBelle, R. BSc, Kendall, C. W.C. PhD, Cunnane, S. C. PhD (2008). Fish-oil supplementation in patients with implantable cardioverter defibrillators: a meta-analysis. CMAJ 178: 157-164 [Abstract] [Full text]  
• Smith, L., Watson, M., Gates, S., Ball, D., Foxcroft, D. (2008). Meta-Analysis of the Association of the Taq1A Polymorphism with the Risk of Alcohol Dependency: A HuGE Gene-Disease Association Review. Am J Epidemiol 167: 125-138 [Abstract] [Full text]  
• Jefferson, T., Foxlee, R., Mar, C. D., Dooley, L., Ferroni, E., Hewak, B., Prabhala, A., Nair, S., Rivetti, A. (2008). Physical interventions to interrupt or reduce the spread of respiratory viruses: systematic review. BMJ 336: 77-80 [Abstract] [Full text]  
• Dekkers, O. M., Biermasz, N. R., Pereira, A. M., Romijn, J. A., Vandenbroucke, J. P. (2008). Mortality in Acromegaly: A Metaanalysis. J. Clin. Endocrinol. Metab. 93: 61-67 [Abstract] [Full text]  
• Arbyn, M., Bergeron, C., Klinkhamer, P., Martin-Hirsch, P., Siebers, A. G., Bulten, J. (2008). Liquid Compared With Conventional Cervical Cytology: A Systematic Review and Meta-analysis. Obstet Gynecol 111: 167-177 [Abstract] [Full text]  
• Cosgrove, M. P., Sargeant, L. A., Griffin, S. J. (2008). Does depression increase the risk of developing type 2 diabetes?. Occup Med (Lond) 58: 7-14 [Abstract] [Full text]  
• Beynon, S., Soares-Weiser, K., Woolacott, N., Duffy, S., Geddes, J. R. (2008). Psychosocial interventions for the prevention of relapse in bipolar disorder: systematic review of controlled trials. Br. J. Psychiatry 192: 5-11 [Abstract] [Full text]  
• Wang, G.-Y., Lu, C.-Q., Zhang, R.-M., Hu, X.-H., Luo, Z. W. (2008). The E-cadherin Gene Polymorphism 160C->A and Cancer Risk: A HuGE Review and Meta-Analysis of 26 Case-Control Studies. Am J Epidemiol 167: 7-14 [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]