NCBI Bookshelf. A service of the National Library of Medicine, National Institutes of Health.
National Academy of Sciences. The Science of Science Communication III: Inspiring Novel Collaborations and Building Capacity: Proceedings of a Colloquium. Washington (DC): National Academies Press (US); 2018 May 16.
The Science of Science Communication III: Inspiring Novel Collaborations and Building Capacity: Proceedings of a Colloquium.
Show detailsImportant Points Made by the Presenter
- Economists and other social scientists tend to make exact predictions of policy outcomes while rarely expressing uncertainty. (Manski)
- Maintaining trust may require ways of communicating uncertainty so that false predictions do not undermine the credibility of science. (Manski)
Communicating uncertainty is one of the biggest challenges journalists face, said Laura Helmuth, national editor of health, science, and environment at The Washington Post, who moderated the session at the colloquium on uncertainty in science communication. Uncertainty is hard to explain and understand. Journalists typically have so much to explain in their stories that they can be tempted to leave uncertainty out. “You have to pick your explanatory battles, and this is a battle that we often put off,” said Helmuth.
But journalists are getting better at it, she added. They are becoming more aware of how uncertainty can be misused, as was the case when the tobacco industry argued that the health effects of smoking were uncertain. They have learned to avoid the trap of false balance, so as not to overstate the uncertainty that exists. “We're getting better at covering uncertainty as a subject in an interesting way,” said Helmuth.
PREDICTIONS WITHOUT MEASURES OF UNCERTAINTY
Scientific evaluations of public policies should explicitly express the limits to knowledge. However, policy analysis “with what I call incredible certitude has been common,” said Charles Manski, Board of Trustees Professor of economics in the Department of Economics at Northwestern University. The predictions that researchers make are often fragile, resting on unsupported assumptions and limited data (Manski, 2013), but economists and other social scientists tend to make exact predictions of policy outcomes while rarely expressing uncertainty. “It's not that they're fraudulent,” said Manski. “It's that you assume more than you have the basis to assume using the data that you have.”
Good examples, he observed, are the predictions, known as scores, made by the Congressional Budget Office (CBO) of the budgetary implications of pending federal legislation. The impacts of new legislation are difficult to foresee, yet the CBO makes 10-year point predictions, with no quantitative measure of uncertainty. Similarly, official statistics from federal agencies, such as the gross domestic product growth rate or the poverty rate, suffer from various kinds of errors, yet agencies typically report only point estimates.
Some agencies do aim to communicate uncertainty transparently. A notable case is the National Weather Service, which in a tweet issued on August 27, 2017, as rainfall from Hurricane Harvey was beginning to inundate Southeast Texas, said, “This event is unprecedented & all impacts are unknown & beyond anything experienced.”
Manski listed several manifestations of incredible certitude. One is conventional certitude, which he described as statistics or estimates that are accepted as true by society but may not be true. Dueling certitudes are contradictory predictions made with alternative assumptions, as when analysts draw opposite conclusions about such issues as illegal drug policies. Conflating science and advocacy is when analysis aims to generate a predetermined conclusion, as with the practice of “model shopping,” where advocates for a particular position go looking for a model that supports their views. Wishful extrapolation is using untenable assumptions to extend a conclusion in a desired direction, as when limited studies of drug outcomes are used to predict what will happen in clinical practice. Illogical certitudes draw unfounded conclusions based on deductive errors, as with research that misinterprets the heritability of personal traits. Finally, media overreach is when journalists do premature or exaggerated reporting of policy analysis.
THE RISKS OF IGNORING UNCERTAINTY
Why do researchers express certainty when they should be expressing uncertainty? Manski pointed to two reasons. The first is that the scientific community tends to reward strong and novel findings. The second is that the public wants unequivocal policy recommendations. Analysts at the CBO, for instance, know that their point estimates should be accompanied by ranges of uncertainty. But they may believe, Manski speculated, that the members of the U.S. Congress are psychologically or cognitively unable to deal with uncertainty. (Although, he added, such estimates in the United Kingdom do include uncertainty.) Or they may believe, because the CBO has established an admirable reputation for impartiality, that it is best to leave well enough alone and have the CBO express certitude when it scores legislation, even if the certitude is conventional rather than credible.
The problem with this approach, said Manski, is that the existing social contract to take CBO scores at face value could eventually break down. Maintaining trust may require expressing uncertainty. “Once you accept incredible certitude and take numbers at face value when they shouldn't be, there may be a slippery slope from incredible certitude to utter disregard for truth. I do not think this is a second-order issue. In fact, it may be even more important to face up to uncertainty today than in the past.”
The Science Behind the News: Gene Drive
Gene drive refers to a technology in which the DNA of a sexually reproducing organism is altered so that most or all of its descendants, not just the typical one-half of its descendants, inherit a particular DNA segment. The technology has different methods, outcomes, and goals, said Fred Gould, University Distinguished Professor of Agriculture in the Entomology Program at North Carolina State University. It can be aimed at eradicating a species, preserving a species, or eliminating the transmission of a disease. It can be spatially or temporally restricted. It can suppress a population rather than eliminate it. However, because gene drive is a new technology, many of its applications cannot yet be foreseen.
Gene drive could also have harmful consequences, Gould observed. A DNA sequence targeted at one group of organisms could spread to other groups. Changes in an organism could alter the ecosystem of which that organism is a part. Some specific types of gene drives may be built in the future that could eliminate a group of organisms or species. The question people inevitably will ask, said Gould, is “Are you playing God?”
The day before the colloquium, two articles on gene drive were released, one in the journal PLoS Biology as an opinion piece (Esvelt and Gemmell, 2017), and the other, before peer review, in the online archive bioRχiv (Noble et al., 2017). These two articles led to a wide variety of headlines, noted Gould, including “Genetically Engineering the Natural World, It Turns Out, Could Be a Disaster” (in Gizmodo), “‘Gene Drives' Are Too Risky for Field Trials, Scientists Say” (in The New York Times), “New Zealand's War on Rats Could Change the World” (in The Atlantic), and “New Model Warns About CRISPR Gene Drives in the Wild” (in Quanta).
The abstracts of the articles themselves give a better sense of their contents, noted Gould. The abstract of the first article said that New Zealand is considering gene drives as a way to locally eliminate mammalian pests and that the article will explore the risk of accidental spread following deployment, concluding that open and international discussions are needed about a technology that could have global ramifications. However, these international discussions have been going on for nearly a decade, Gould observed, raising questions about why the researchers ignored previous work of their colleagues in raising such an alarm and why journalists amplified this alarm without checking with other sources.
The abstract of the second article noted that even the least effective gene drive systems reported to date are highly invasive and that “standard drive systems should not be developed nor field tested in regions harboring the host organism.” However, the best gene drive system tested so far was not even effective at spreading in the laboratory, much less in the field, Gould noted.
How did the two papers released the day before the colloquium become such a big news story? A major reason is that gene drives are being discussed in such apocalyptic terms, Gould said. Headlines such as “Reckless Driving: Gene Drives and the End of Nature,” as one article from a group of advocacy organizations was titled, raise questions about the responsibilities of researchers and professional journalists communicating about the issue. Perhaps some kind of “rules of the road” would help researchers engage with journalists in ways that would provide for more accurate reporting of scientific findings. Gould suggested that we need to ask what is the responsibility of the researcher and what is the responsibility of the journalist.
One of the authors of the first article, Kevin Esvelt, “has been doing something rather unusual in science,” said Pam Belluck, a health and science writer for The New York Times. As part of his research into the use of gene drives to help eliminate Lyme disease from Nantucket Island, he has been allowing the community to decide whether to allow tests of the technology to occur. He has published his plans online, has made several presentations on Nantucket, and has formed steering committees that deliberately include skeptics and critics. This process has led the people of Nantucket to decide that they do not want to test gene drive, partly because it will result in bacterial genes being added to the mouse genome and partly because of possible undesirable side effects. Esvelt's approach has been praised for its outreach to the public and his willingness to change plans when the community expressed its feelings about the research.
In the perspective piece published the day before the colloquium, Esvelt and his coauthor took a much more cautious approach toward gene drive than they had in the past, writing that “now is the time to be bold in our caution.” Esvelt still contends that gene drive might have applications for a plague like malaria, Belluck noted, but for now gene drive is off the table on Nantucket, even as other options are being considered to deal with Lyme disease.
Gene drive is an example of what Dominique Brossard, professor and chair of the Department of Life Sciences Communication at the University of Wisconsin–Madison, called postnormal science, where the uncertainty and stakes surrounding an issue are both high. Such issues involve not just technical risk assessments but legal, moral, social, and cultural implications. Therefore, they can generate very strong feelings in the public. The Science, Media, and the Public research group at the University of Wisconsin–Madison recently collected survey data on what Americans thought about editing genes in wildlife populations. In response to the question, “Does editing genes in wildlife population mess with nature?” more than 60 percent of respondents agreed, and 60 percent agreed that it “allows humans to play God” (Kohl et al., 2017). However, the wording of the question can make a big difference, Brossard noted. The largest response when people were asked whether “editing genes in wildlife to decrease or eliminate local populations of animals or plants that are causing environmental problems is morally acceptable” was “neither agree nor disagree,” with a rough split between people who agreed with the statement and those who disagreed.
The moral context varies from place to place depending on such factors as regulation, laws, institutional rules, and religiosity, Brossard observed. In addition, the impact of a message in the media differs from place to place and among populations. For example, using genetically engineered mosquitoes as a method to reduce the threat of Zika is one circumstance under which Americans who otherwise would be reluctant to support genetic engineering may be willing to accept it as a solution to a public health problem that might personally affect them (Lull et al., 2017).
- Communicating Uncertainty - The Science of Science Communication IIICommunicating Uncertainty - The Science of Science Communication III
Your browsing activity is empty.
Activity recording is turned off.
See more...