How the quality of the scientific literature impacts the evidence

by Tom Lang and George Lundberg, MD

A not-so-obvious truth is that evidence-based medicine is literature-based medicine.

That is, the quality of the scientific literature directly affects the quality of the evidence.

Quality, in turn, depends in large measure on reporting research completely and accurately.

In response to ample evidence that such quality is often missing from the literature, dozens of reporting guidelines, such as the CONSORT Statement for reporting randomized trials, are now available on the Equator Network website.

Such guidelines as these do appear to have improved the quality of published research.

But another aspect of quality in writing is clarity; the need for writing to be both easily understood and seldom misunderstood.

To write clearly, authors have to know their topic, of course, but they also have to know how to say something, which in turn depends on to whom they are saying it and why.

Writing clearly is difficult for many medical and scientific authors because they have never been taught how to communicate technical information in writing.

We know a good deal about this topic.

We know that using common words, less-complex sentences, the active voice, strong topic sentences, and so on, make writing easier to understand.

Many writers in the sciences would do well to review those lessons. But the more important skills are to develop a sense of audience and to write with a specific purpose.

“Reader-based writing” is writing that actually meets the information needs of readers, not the author’s need for expression.

To do this, authors must constantly remind themselves about “what their readers already know, want to know, need to know, don’t know, and think they know that isn’t so.”

Clear writing also has a specific purpose.

The purpose of scientific writing is not to inform; information for its own sake has little value.

Rather, the purpose is to help readers act; to change the way they practice medicine or conduct research.

All you authors need to identify your purpose — what you want your readers to do — and then organize your thoughts and write accordingly.

Don’t only provide the evidence about evidence-based medicine; provide it with clarity of expression, of audience, and of purpose.

Tom Lang is the author of How to Write, Publish, and Present in the Health Sciences and How to Report Statistics in Medicine, and is also an international consultant in the fields of scientific publications and written communication. George Lundberg is a MedPage Today Editor-at-Large and former editor of the Journal of the American Medical Association.

Originally published in MedPage Today. Visit for more health policy news.


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  • Marc Gorayeb, MD

    “The purpose of scientific writing is not to inform; information for its own sake has little value. Rather, the purpose is to help readers act; to change the way they practice medicine or conduct research.”

    That approach seems a bit too proactive or agenda-driven for my taste. I don’t want the scientists I read to have a purpose to help me to act, to change the way I practice medicine. What I want from them is a slice of the truth or reality, whether or not it gets me to change my practice.

  • Tom Lang

    Writing to help people act means giving them the information they need to make any given decision, not to push that decision in any particular direction. Readers read for functional reasons (as opposed to recreational reasons), and many authors who do not consider what these functional reasons might be. As a result, their writing may be incomplete, unfocused, or both, which can waste a readers time by not meeting their needs for information.

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