[Significance of letters published in the Dutch Journal of Medicine, 1997/98]

To determine whether in the correspondence section of the Nederlands Tijdschrift voor Geneeskunde (Dutch Journal of Medicine, NTvG) serious criticism is formulated or important mistakes in the original articles are pointed out.

Descriptive, retrospective bibliometric study.

Correspondence in the period July 5, 1997-June 27, 1998 published in the NTvG (n = 196 letters) was scored for 10 items and categorized in categories: 'agree', 'do not agree' (criticizing methods or results or interpretation, or unmotivated criticism) and 'political reaction'. The questions were studied to what category of published articles the letters referred and how many letters referred to the same articles. 22 letters from the period October-December 1998 were judged separately as the peer review reports of the original articles were still available.

In 115 (58.7%) letters the writers expressed agreement with the original article. Almost 40% (77) of the 196 letters contained scientific discussion on the subject in question. Most reactions concerned 'Original articles' (25%) and 'Clinical lessons' (19.4%). In 8/196 (4.1%) a mistake was revealed; 6 of these reactions led to the publication of a 'Correction' (to 3 articles). There was no criticism which would have led to rejection of the article involved had it been known before publication. The letters about articles of which the peer reviews were still available contained no criticism of points the peer reviewers had missed.

Of the correspondence letters of the NTvG 4.1% contained scientific criticism which could have led to changes in the article if it had been known before publication.