The publication of medical research is prone to error. Misuse of statistics, selective citation of published work, misquotation of references, and overenthusiasm in the search for positive findings are crimes, often committed unwittingly, that can escape peer review before a paper is published.1 Only after publication can a piece of research be exposed to the sort of critical review, by journal readers, that can either establish its place or consign it to the dustbin. The potential of correspondence as a form of peer review is supported by editors2 - the BMJ reserves its letters pages almost exclusively for comment on published material - but it remains underdeveloped and undervalued by clinicians, academics, teachers, and many journals.

In four specialist journals examined by Spodick and Goldberg only 2% of the space was devoted to letters from readers.3 Four general journals gave 15% of the space to letters, but fewer than half referred to original papers. Dr Steven Spiro, editor of Thorax, says he receives only about four letters an issue (the journal received only 37 in 1993). He encourages letters referring to original research and publishes most that come in, usually with a response from the authors. Last year the Annals of Rheumatic Diseases, a monthly journal, received only 84 letters and the British Journal of Ophthalmology, also a monthly, received only 37. …