Introducing... Reproduced and modified from a presentation produced by Zoë Debenham from the original presentation created by Kate Light, Cochrane Trainer at the NHS CRD: 07/08/02]

Learning Outcomes u To understand what the Cochrane Library is and when to use it u To understand how to carry out straightforward searches using the Cochrane Library

Access to the Cochrane Library u Available from any computer with internet access (work or home) u No password required u Web address: u Access also via NLH (

What is the Cochrane Library? u Database providing reliable evidence about effectiveness of interventions such as: u Treatment u Diagnosis and screening u Health promotion u Organisation of care

When should you use the Cochrane Library? u For questions about effectiveness: u What is the effectiveness of treatment x e.g Does hypnotherapy increase smoking cessation? u What is an effective treatment for y e.g What is the best treatment for epilepsy? u Is z effective in treating y or, is z better than x at treating y e.g Is feather bedding better than non-feather bedding for asthma sufferers?

When should you not use the Cochrane Library? u For general healthcare questions u causal, prognosis, epidemiology, etc. u e.g. what causes senile dementia? u Statistics u prevalence and incidence u Primary research other than RCTs & CCTs u Current Research

Levels of evidence (In order of decreasing scientific validity) u Systematic review u Well conducted randomized controlled trials of appropriate size u Well-designed non-randomised trials u Well-designed non-experimental studies from more than one source u Opinions of respected authorities u “Someone told me”

Systematic Reviews u Comprehensive identification and synthesis of all relevant studies on a given topic, maybe RCTs, maybe other studies u Include: u Comprehensive search strategy (covering both published and unpublished studies) u Clear criteria for study inclusion/exclusion u Analysis of methodological quality of included studies u List of all studies excluded, with justification u Clear analysis of results of eligible studies, including statistical synthesis of data if possible and appropriate u Structured report

Why are systematic reviews so great? u Test theories taking into account all evidence: scientific rather than subjective summary of literature u Can reveal “new” evidence via meta- analysis u Summarise literature on subject u More reliable evidence to aid decision making

The Cochrane Library Databases Methodology Register NHS Economic Evaluation Database Database of Abstracts of Reviews of Effectiveness Controlled Trials Register Database of Systematic Reviews Health Technology Assessment Database About the Cochrane Collaboration Database of Methodology Reviews

Cochrane Database of Systematic Reviews (‘Cochrane Reviews’) u Completed systematic reviews (from the Cochrane Collaboration) u Full text u Ongoing systematic reviews (from the Cochrane Collaboration) u Abstract

Database of Abstracts of Reviews of Effectiveness (‘Other Reviews’) u Abstracts of quality assessed systematic reviews (produced by NHS CRD) u References to systematic reviews awaiting CRD abstracts (produced by NHS CRD) u Other references to reviews (pre1994) not assessed by the CRD

Cochrane Controlled Trials Register (‘Clinical Trials’) u Primary research u References to RCTs with abstracts u Found from extensive hand-searching u References to unpublished trials u The result of the “Medical Editors Trial Amnesty”

Other main databases u Health Technology Assessment Database (HTA) u Not same as UK HTA project u Reports of health technology assessments u Many have structured (but not critical) abstracts u Records of some ongoing projects u Compiled by the NHS CRD u NHS Economic Evaluation Database (EED) u Economic evaluations of healthcare interventions u Detailed structured abstracts u Critical abstracts u CRD commentary on quality of paper

Four good reasons to use the Cochrane Library u Premier resource for information on effectiveness u Full text of maintained systematic reviews u Structured abstracts of other systematic reviews u Single best resource for references to randomised controlled trials.

A perfect Cochrane Library? u Gaps in subject coverage exist u Critical appraisal skills are still necessary u Updated monthly (from January 2010)

How does Cochrane fit in with Medline/Cinahl etc? u Use Cochrane first to identify evidence on: u The effectiveness of interventions u In particular, high quality evidence such as RCTs and Systematic Reviews u Cochrane reviews are indexed on Medline and CINAHL