The Cochrane Library is a collection of databases that contain different types of high-quality, independent evidence to inform healthcare decisions. 

Chief among the seven databases that make up the library is the Cochrane Database of Systematic Reviews. Researchers who conduct systematic reviews use methods that attempt to minimize bias in order to produce more reliable findings; the findings then inform decision making.

There are five types of reviews. Here are two described in detail:

• Intervention - assess the benefits and harms of interventions used in healthcare and health policy.
• Diagnostic test accuracy -  assess how well a diagnostic test performs in diagnosing and detecting a particular disease.

There are also methodology, qualitative and prognosis reviews.

Behind the Cochrane Library and Reviews is a community of about 37,000 people from more than 130 countries working in 14 languages. Many are volunteers. They are researchers, professionals, patients, carers, and people passionate about improving health outcomes for everyone, everywhere.