Systems for grading the quality of evidence and the strength of recommendations II: Pilot study of a new system

David Atkins¹ , Peter A Briss² , Martin Eccles³ , Signe Flottorp⁴ , Gordon H Guyatt⁵ , Robin T Harbour⁶ , Suzanne Hill⁷ , Roman Jaeschke⁸ , Alessandro Liberati⁹ , Nicola Magrini¹⁰ , James Mason³ , Dianne O'Connell¹¹ , Andrew D Oxman⁴ , Bob Phillips¹² , Holger Schünemann⁵^,13 , Tessa Tan-Torres Edejer¹⁴ , Gunn E Vist⁴ , John W Williams Jr¹⁵ and The GRADE Working Group

¹Center for Practice and Technology Assessment, Agency for Healthcare Research and Quality, 540 Gaither Rd. Rokville, MD 20852, USA

²Community Guide Branch, Centers for Disease Control and Prevention, MS K73, 4770 Buford Highway, Atlanta, GA 30341, USA

³Centre for Health Services Research, University of Newcastle upon Tyne, 21 Claremont Place, Newcastle upon Tyne NE2 4AA, UK

⁴Informed Choice Research Department, Norwegian Health Services Research Centre, Pb. 7004 St. Olavs Plass, 0130 Oslo, Norway

⁵Departments of Clinical Epidemiology and Biostatistics and Medicine, McMaster University, 1200 Main Street West, Hamilton, Ontario L8N 3Z5, Canada

⁶Scottish Intercollegiate Guidelines Network, 9 Queen Street, Edinburgh EH2 1JQ, UK

⁷Department of Clinical Pharmacology, Faculty of Medicine and Health Sciences, University of Newcastle, Level 5, New Med 2 Building, Newcastle Mater Hospital, Waratah, NSW 2298, Australia

⁸Department of Medicine, McMaster University, 1200 Main Street West, Hamilton, Ontario L8N 3Z5, Canada

⁹Department of Oncology and Hematology, Università di Modena e Reggio Emilia, Azienda Ospedaliera Policlinico, Via dal Pozzo 41, 41100 Modena, Italia and Centro per la Valutazione della Efficacia della Assistenza Sanitaria (CeVEAS), Modena, Italy

¹⁰Centro per la Valutazione della Efficacia della Assistenza Sanitaria (CeVEAS), NHS Centre for the Evaluation of the Effectiveness of Health Care, Viale Muratori 201, Modena 41100, Italy

¹¹Cancer Epidemiology Research Unit, Cancer Research and Registers Division, The Cancer Council NSW, PO Box 572, Kings Cross NSW 1340, Australia

¹²Centre for Evidence-based Medicine, University Department of Psychiatry, Warneford Hospital, Oxford OX3 7JX, UK

¹³Departments of Medicine and Social & Preventive Medicine, University at Buffalo, State University of New York, ECMC-CC142, 462 Grider St, Buffalo, NY 14215, USA

¹⁴Global Programme on Evidence for Health Policy, World Health Organisation, CH-1211 Geneva 27, Switzerland

¹⁵The Center for Health Services Research in Primary Care, HSR&D, Department of Veterans Affairs Medical Center and Duke University Medical Center, 508 Fulton St., Durham, NC 27705, USA

author email corresponding author email

BMC Health Services Research 2005, 5:25doi:10.1186/1472-6963-5-25


Published:	23 March 2005

Abstract

Background

Systems that are used by different organisations to grade the quality of evidence and the strength of recommendations vary. They have different strengths and weaknesses. The GRADE Working Group has developed an approach that addresses key shortcomings in these systems. The aim of this study was to pilot test and further develop the GRADE approach to grading evidence and recommendations.

Methods

A GRADE evidence profile consists of two tables: a quality assessment and a summary of findings. Twelve evidence profiles were used in this pilot study. Each evidence profile was made based on information available in a systematic review. Seventeen people were given instructions and independently graded the level of evidence and strength of recommendation for each of the 12 evidence profiles. For each example judgements were collected, summarised and discussed in the group with the aim of improving the proposed grading system. Kappas were calculated as a measure of chance-corrected agreement for the quality of evidence for each outcome for each of the twelve evidence profiles. The seventeen judges were also asked about the ease of understanding and the sensibility of the approach. All of the judgements were recorded and disagreements discussed.

Results

There was a varied amount of agreement on the quality of evidence for the outcomes relating to each of the twelve questions (kappa coefficients for agreement beyond chance ranged from 0 to 0.82). However, there was fair agreement about the relative importance of each outcome. There was poor agreement about the balance of benefits and harms and recommendations. Most of the disagreements were easily resolved through discussion. In general we found the GRADE approach to be clear, understandable and sensible. Some modifications were made in the approach and it was agreed that more information was needed in the evidence profiles.

Conclusion

Judgements about evidence and recommendations are complex. Some subjectivity, especially regarding recommendations, is unavoidable. We believe our system for guiding these complex judgements appropriately balances the need for simplicity with the need for full and transparent consideration of all important issues.