Pres. Barack Obama, medical error and gravitational waves all sat atop Digital Science’s third annual Altmetric Top 100 list, which highlights 2016’s most shared scientific publications. Obama’s paper on the progress and next steps for health care reform in JAMA The Journal of the American Medical Association came in first place, and received the highest Altmetric Attention Score ever.

Altmetric analyzes how articles percolate across the Web—you may have seen the little rainbow doughnut and number accompanying scientific publications. The score tracks article performance on social media sites like Facebook and Twitter as well as news outlets, Wikipedia and other forums. The increasing number of folks sharing journal articles online marks the importance of making research available and communicating it accurately to a broader audience, says Altmetric founder Euan Adie. He cautioned, however, that the Top 100 list highlights the most shared papers, not necessarily the best ones, because Altmetric does not measure positive versus negative attention. “These are just the ones that are capturing the imagination,” he says.

Credit: Amanda Montañez; Source: Altmetric Top 100 Articles of 2016

Medical science papers, unsurprisingly, occupy 49 of the 100 slots. Those relating to topics in the news, such as Zika virus and microcephaly, created lots of buzz: “Zika Virus and Birth Defects—Reviewing the Evidence for Causality,” published in The New England Journal of Medicine, came in at number six. Other high-scoring papers also covered public health topics likely to interest big audiences: a study on how income relates to life expectancy, published in JAMA, took seventh place; a JAMA Internal Medicine investigation that showed the sugar industry funded studies downplaying the effects of sugar on coronary heart disease came in fifth; and a report finding that medical error was the third leading cause of death in the U.S., published in the British Medical Journal, came in at number two. This is consistent with a Scientific American analysis of “buzzworthy” papers, published this past October, which also tilted toward the life sciences.

Obama’s paper appearing at the top of the list makes sense, given the author’s job title. But Adie thought this was a special case, noting the document was not peer-reviewed. Plus, although Obama was probably the first chief executive to have written a complete scientific paper, presidents Bill Clinton and George W. Bush have published opinions in academic journals in the past.

Adie notes a couple of surprises on this year’s list. “This was the first time we saw preprints from the life sciences in the Top 100,” he says. Physicists have long used the arXiv preprint servers to make research available ahead of peer review and publication, so the scientific community can see and judge work quickly. This year, a study from the preprint server bioRxiv appeared at number 21; another from PeerJ took 28th place. Adie was also surprised that this year only saw a small increase in open-access articles over last year—from 42 to 47—and that two astronomy papers appeared in the top 10, one on gravitational waves and the other on the theoretical Planet Nine. “Normally that doesn’t happen,” he says.

The list ultimately serves as a reminder that people actually read scientific papers. “When you publish a piece of research,” Adie says, “it’s not just your peers who see it. It’s potentially a much broader audience.”