Types of Papers

In terms of hierarchy of evidence a meta-analysis of randomised controlled trials is always accorded the highest level of evidence. It would be followed by a prospective, double blinded, randomised controlled trials. Systematic reviews can give very good information as can observational studies although clearly more value is obtained when these studies are undertaken prospectively than retrospectively. Cohort studies are usually prospective and often compared to groups one with a none risk factor and one without, the groups being followed to assess the later development of disease or of an outcome and risk factors are reported as a relative risk.

Again, in a case controlled study which is usually retrospective and observational involving two groups, there are those with an outcome of interest (cases) and those without (controls). The controls may be a previously investigated group (historical controls). This type of study can allow for the analysis of many factors and the strength of association is usually given as an odds ratio.

A case series is also retrospective and only reports one group of patients often undertaken by a single observer and requires complete data collection and 100% follow-up to avoid significant bias.

Case reports are required to be particularly educational or illustrative of a new form of treatment in order to merit publication.