[The structured summary: a tool for reader and author]

To determine and to compare the information contained in structured abstracts in original articles in Annals of Internal Medicine (AIM), British Medical Journal (BMJ), New England Journal of Medicine (NEJM) and of abstracts that have been published in Nederlands Tijdschrift voor Geneeskunde (NTvG).

Editorial office NTvG.

Descriptive.

Critical reading of 15 original articles of AIM (5), BMJ (5) and NEJM (5) in 5 consecutive issues starting from 1 March 1990 and all original articles of 6 consecutive issues of NTvG starting from 7 april 1990. According to the criteria of the 'ad hoc working group for critical appraisal of the medical literature' the amount of information in all foreign abstracts and 10 selected abstracts of NTvG were determined. The authors made structured abstracts of all read articles of NTvG.

Structured abstracts of AIM, BMJ and NEJM are clear and detailed. However information about key sociodemographic features of patients, their selection and the way of statistical analysis of the results was often missing. In NTvG articles essential information was lacking with respect to objective, design, setting of the study, sociodemographic features of patients, and patients and methods. Structured abstracts of articles in NTvG take more space: an average of 266 instead of 164 words.

Structured abstracts take more space but are more informative. Authors of original articles in NTvG are advised to prepare structured abstracts. Editors and peer reviewers should ascertain that no essential information is lacking.