The Use of Cause-and-Effect Language in the JAMA Network Journals

As a manuscript editor and freelance manuscript editing coordinator for the JAMA specialty journals, I am constantly having to edit out cause-and-effect language from observational studies that are not randomized clinical trials. According to the AMA Manual of Style, the word effect, as a verb, means to bring about a change; as a noun, it means result.

A randomized clinical trial is one of the few types of studies that are designed to assess the efficacy of a treatment or intervention (and thus allowed to use cause-and-effect language) because the participants are treated in controlled, standardized, and highly monitored settings.

Whenever I come across a study in which the authors are trying to determine, for example, whether the use of a certain type of drug will reduce the risk of some complication following a certain type of surgery, I need to verify whether the study is a randomized clinical trial or a report of a controlled laboratory experiment. If it isn’t, and is a report of an observational study (such as a cohort, cross-sectional, case-control, or case series study, or a meta-analysis), then all cause-and-effect language must be replaced. But by what?

Generally, association may be a useful replacement for effect. The AMA Manual of Style defines association as a “statistically significant relationship between 2 variables in which one does not necessarily cause the other. When 2 variables are measured simultaneously, association rather than causation generally is all that can be assessed.” So instead of saying the “effect of this on that,” rephrase as the “association of this with that” or the “association between this and that.”

Sometimes, however, the authors don’t agree and want me to change it back, in which case I calmly let the authors know that it is AMA style to allow cause-and-effect language only for randomized clinical trials and controlled laboratory experiments and that, perhaps in the “Discussion” section of their manuscript, they can try to make arguments to support that the association might be causal. However, to quote from one of our scientific editors, “the expression and ultimate interpretation of the findings can’t be causal.”

The use of cause-and-effect language is quite common in everyday speech, and so it is easy for most people to assume that if one event comes before another, then the first is the cause of the second. In the JAMA Network journals, findings that rely on this type of logic had to have been rigorously tested in a randomized clinical trial.—Paul Ruich

 

Questions From Users of the Manual

Q: Section 3.12.5 describes how to cite books with editors and translators but there is no example showing how to cite a book with both an editor and an editor in chief. Should only the editor in chief be cited if one is given for a book?

A: No, I would not exclude other editors’ names if an editor in chief is given. You could extrapolate from the example in section 3.12.5 that shows how to cite an editor and a consulting editor. In that example, repeated below, just replace “consulting ed” by “ed in chief.”

Klaassen CD. Principles of toxicology and treatment of poisoning. In: Hardman JG, Limbird LE, eds. Gilman AG, consulting ed. Goodman and Gilman’s The Pharmacological Basis of Therapeutics. 10th ed. New York, NY: McGraw-Hill Book Co; 2001:67-80.

Q: When you cite an online reference that will require a password to access the reference, should you include in the reference citation some indication that access is restricted?

A: We wrestled with this question when preparing the current edition and decided against it because different users would have different access rights.

Q: When citing the same work 2 or more times in a manuscript, do you continue to use the same superscript reference number, or do you use a different superscript reference number and relist the work multiple times in the reference list?

A: It is our style to give a reference one number and to refer to it by that number every time it’s cited. This policy is not stated specifically in the manual and perhaps in the next edition it should be. In the current edition, page 44 discusses the situation in which an author might want to cite different (and specific) page numbers from the same reference. The style used is based on the assumption that a reference number “sticks” throughout a manuscript.

Q: Your manual (pp 22 and 183 in print) advises that clinical trials should be registered and that the URL of the registry and the identifying number should be published as a part of the manuscript. Is this still true if the clinical trial has been terminated?

A: Yes, the identifier should be given even if the clinical trial has been terminated. Anyone who chooses to go to the URL provided will be able to read about the trial and will also see there that it has been terminated.—Cheryl Iverson, MA