How to read a research paper: Reading between and beyond the lines

BACKGROUND: Despite peer review, publications in scientific journals are not always well written, sometimes contain errors, and often exhibit deliberate or unintended biases. It is necessary to learn how to identify such limitations. It is also necessary to learn how to read between and beyond the lines of papers no matter how well written they are and no matter how highly ranked the journal is. MATERIALS AND METHODS: This paper critically examines an important article in a leading journal with a view to help the reader learn how to place the findings of a study in perspective, understand its limitations, and glean information beyond that actually presented and discussed in the text. RESULTS: Several issues are examined; these relate to case–control research designs, confounding, propensity matching, absolute risk, confidence intervals, interpretation of findings, real-world relevance, ecological validity, and definition of a cause–effect relationship. CONCLUSIONS: The issues examined in this paper reflect common themes in research, and a reader aware of these themes will more easily identify them in his future readings.