Traditional clinical review articles, also known as updates, differ from systematic reviews and meta-analyses. Systematic reviews comprehensively examine the medical literature, seeking to identify and synthesize all relevant information to formulate the best approach to diagnosis or treatment. Meta-analyses, sometimes known as quantitative systematic reviews seek to answer a narrow clinical question, often about the specific treatment of a condition, using rigorous statistical analysis of pooled research studies. Updates review the medical literature almost as carefully as a systematic review but discuss the topic under question more broadly and make reasoned judgements where there is little hard evidence, based upon the expertise of the reviewer. It may not include evidence from foreign language journals or look for unpublished data on a topic, so will tend to be more applicable to the local situation than a systematic review, as it may take into account local shortages of equipment or personnel.