Junkfood Science: Action words: One word can change everything

December 26, 2007

Action words: One word can change everything

In today’s soundbyte world, blurbs and headlines are often shaved of their accuracy in an attempt to make a health story sound splashier and action-packed. The story may be more likely to grab our attention, but all too often it also reports what the original study did not, and could not, conclude.

Health News Review has published a simple and very helpful piece focused on one aspect of this problem: understanding causal language. Directing their concerns to health journalists writing stories and headlines, they caution against changing adjectives (“lower risk”) to verbs (“lowered” the risk) when reporting on epidemiological studies. Why? That simple switch changes the meaning: from a correlation to imply a causation. Nouns can suffer similar degradations during wordsmithing.

Their explanation of the types of study designs and the limitations of each may be helpful to journalists, but also for readers to help recognize when news reports have stepped beyond credibility. Does eating fish preserve your eyesight or cut your risk of dying of a heart attack? Does drinking coffee lower your risks for diabetes? Can aspirin prevent cancers? Does drinking alcohol increase your risk for breast cancer? In actuality, it was not even possible for the studies that examined these correlations to answer any of these questions. But how many news reports made that clear?

This valuable article is here, and begins:

Publisher's Corner

A health writer’s first attempt at expressing results from a new observational study read, “Frequent fish consumption was associated with a 50% reduction in the relative risk of dying from a heart attack.” Her editor’s reaction? Slash. Too wordy, too passive. The editor’s rewrite? “Women who ate fish five times a week cut their risk of dying later from a heart attack by half.” This edit seems fair enough – or is it? The change did streamline the message, but with a not-so-obvious, unintended cost to the meaning.....

The authors go on to describe epidemiological studies and randomized trials, highlighting one of the most crucial and most misunderstood differences:

Epidemiologic – or observational – studies examine the association between what’s known in epidemiologic jargon as an exposure (e.g., a food, something in the environment, or a behavior) and an outcome (often a disease or death). Because of all the other exposures occurring simultaneously in the complex lives of free-living humans that can never be completely accounted for, such studies cannot provide evidence of cause and effect; they can only provide evidence of some relationship that a stronger design could explore further..... The only study design involving humans that does rise to the level of demonstrating cause and effect is a randomized trial.... Because observational studies are not randomized, they cannot control for all of the other inevitable, often unmeasurable, exposures that may actually explain results. Thus, any link between cause and effect in observational studies is speculative at best.

During the writing, editing and headline composing are all opportunities for imprecise wordsmithing that can imply causation from correlations, they caution. Other sources of such mistakes for health journalists, they said, are borrowing the language found in press releases or as expressed by some researchers when describing the results of epidemiological studies. These errors can mislead readers into believing that a cause or treatment has been found, to overestimate the value of the study findings, or even to make life decisions that the evidence doesn’t support.

However, to be fair to the best writers, and as a caveat to readers tempted to skim headlines for the gist of the health news, very few writers write the headlines that accompany their articles or even get to see them before they go to press. Headlines are often written by copy writers, who you can be pretty sure don’t have science or medical degrees, nor read the study.

As the authors noted, it’s important to pay attention to language and the subtle ways that word choices can imply cause-and-effect relationships when a study design does not support such conclusions. That’s advice we all can use!

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