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Systematic Reviews

This guide will introduce you to the process of conducting a systematic review.

Tools for Assessing the Quality of Studies

IOM Standard: 3.6 Critically appraise each study

3.6.1 Systematically assess the risk of bias, using predefined criteria

3.6.2 Assess the relevance of the study's populations, interventions, and outcome measures

3.6.3 Assess the fidelity of the implementation of interventions

Cochrane Manual

See Chapter 8: Assessing risk of bias in included studies

JAMAevidence - Users' Guides

Chapters on evaluating studies

Jadad Scale

The Jadad Scale, sometimes known as Jadad scoring or the Oxford quality scoring system, is a procedure to independently assess the methodological quality of a clinical trial. Jadad et al. published a three-point questionnaire that formed the basis for the Jadad score.

Jadad, A.R., Moore, R.A., Carroll, D., Jenkinson, C., Reynolds, D.J.M., Gavaghan, D.J., & McQuay, H.J. (1996). Assessing the quality of reports of randomized clinical trials: Is blinding necessary?. Controlled Clinical Trials, 17(1): 1-12. PMID 8721797

GRADE Working Group

The working group has developed a common, sensible and transparent approach to grading quality of evidence and strength of recommendations.

Assessing the Risk of Bias of Individual Studies in Systematic Reviews of Health Care Interventions

From AHRQ - "Methods Guide for Effectiveness and Comparative Effectiveness Reviews"

Avoiding Bias in Selecting Studies

From AHRQ - "Methods Guide for Effectiveness and Comparative Effectiveness Reviews"

The Newcastle-Ottawa Scale (NOS) for assessing the quality of nonrandomised studies in meta-analyses

Nonrandomized studies, including case-control and cohort studies, can be challenging to implement and conduct. Assessment of the quality of such studies is essential for a proper understanding of nonrandomized studies. The Newcastle-Ottawa Scale (NOS) is an ongoing collaboration between the Universities of Newcastle, Australia and Ottawa, Canada. It was developed to assess the quality of nonrandomized studies with its design, content and ease of use directed to the task of incorporating the quality assessments in the interpretation of meta-analytic results.

Levels of Evidence

GRADE Working Group

The Grading of Recommendations Assessment, Development, and Evaluation (GRADE) Working Group began in the year 2000 as an informal collaboration of people with an interest in addressing the shortcomings of present grading systems in health care. The working group has developed a common, sensible and transparent approach to grading quality of evidence and strength of recommendations. Many international organizations have provided input into the development of the approach and have started using it.

Levels of Evidence and Grades of Recommendations

Oxford-Centre for Evidence Based Medicine

Strength of recommendation taxonomy (SORT): a patient centered approach to grading evidence in the medical literature.

Am Fam Physician. 2004 Feb 1;69(3):548-56. PMID 14971837

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