ACC Guide to the Cochrane Library

This brief glossary covers health research terms that have been used in the Guide. If there are words which appear in the Guide that you think it would be helpful to include in the glossary, please let us know. We shall develop the glossary as the scope of the Guide develops. A more extensive glossary of health research can be found on the website of Informed Health Online.

Abstract
A brief summary or digest of the study and its results. It should tell you what the study tried to show, how the researchers went about it, and what they found. This is often the only part of the content of an article that will show up on a database.

Adverse reaction (also adverse event or side effect)
An unfavourable, or even harmful effect or event resulting from a health care treatment or procedure.

Bias
Any factor, recognised or not, that alters presentation or availability of data, effects of treatment, or assessment of findings by study participants, researchers, publishers or reviewers themselves.

Cochrane Collaboration
A not-for-profit international organisation that aims to help people make well-informed decisions about health care. This is achieved through the preparation of systematic reviews drawing together information obtained from well-conducted studies. The reviews are published in the Cochrane Database of Systematic Reviews – one of the components of the Cochrane Library. It is a registered charity in the United Kingdom.

Consumers
People who use or are potential users of health services.

Controls
The group in a clinical study who are receiving treatment other than that being investigated. Controls may receive no treatment, a placebo, or a commonly used treatment for that condition that acts as a marker of effectiveness.

Database
A collection of organised information, usually held on a computer.

Effectiveness
The extent to which an intervention does people more good than harm. An effective treatment or intervention is effective in real life circumstances, not just in an ideal situation.

Empirical
Based on experience or observation rather than on reasoning alone.

Full-text
Where the complete text of a document or record is provided.

Handsearching
Within the Cochrane Collaboration handsearching refers to manually looking through publications (usually journals and/or conference proceedings) page by page to identify all reports of randomised trials that may not appear in electronic databases.

Health Care Technology
An internationally recognised term that covers any method used by those working in health services to promote health, prevent and treat disease and improve rehabilitation and long-term care. Health technology assessments look at the medical, social, ethical and economic implications of various technologies (e.g. pharmaceuticals, vaccines, medical and surgical procedures) with a view to informing policy decisions.

Intervention
A treatment or procedure (e.g. surgery, a drug, a test, treatment counselling, an information leaflet) that is used to change the course of a state of being, trauma or disease process.

IP address
Every computer that communicates over the Internet is assigned an Internet Protocol (IP) address that uniquely identifies the device and distinguishes it from other computers on the Internet. An IP address consists of 16 numbers from 0-255 represented in decimal form, e.g. 168.212.226.204. A component of the IP address can be used to help identify the country where the computer sits.

Meta-analysis
A way of grouping information or data from a number of different studies to determine an average or common effect. It is aimed at improving the precision of the available data by looking at a greater number of people. It may not be possible for a meta-analysis to be included in a review because data from different studies cannot always be combined.

Placebo
A treatment that to all intents and purpose appears to be the same as the known treatment that is being assessed, but which does not have an active ingredient.

Practice guidelines
Systematically developed statements, policies, general requirements or recommendations for determining a course of action in specific circumstances. Often produced by professional societies or colleges.

Randomised controlled trial (RCT)
In a randomised trial participants are assigned by chance to receive either an experimental or control treatment. The idea behind the randomised trial is that when it is done properly, the effect of a treatment can be studied in groups of people who are the same at the outset, and treated in the same way, except for the intervention being studied. Any differences then seen in the groups at the end of the trial can be attributed to the difference in treatment alone, and not to bias or chance.

Systematic review
A means of capturing the volumes of information from clinical studies. This is done in a set way to minimise bias and potential errors in any one study, and so provides reliable information on whether a clinical treatment can work as a basis for making health care decisions.

Sources used: Cochrane Collaboration glossary (Cochrane Library, Issue 3, 2004), Dictionary of Research Terms for Consumers available at Informed Health Online and the glossary produced by the Norwegian branch of the Nordic Cochrane Centre.