Altmetrics: Broadening Impact or Amplifying Voices?

A large portion of research investment across the globe is generated from public funds, and there is thus considerable effort aimed at demonstrating to the public the impact of their investment. Broader impacts, however, are not easily measured. Efforts have been made to use translation, application, and technology transfer as evidence of broader impact. Open access publishingsuch as practiced by ACS Central Sciencehas been heralded as another potential avenue to achieve this broader dissemination. As science has moved online, so too have its indicators. Advances in digital technology have given rise to a new form of indicatorsaltmetricswhich are based on quantitative evidence of interactions with research objects online, primarily through social media platforms. The goal of altmetric indicators is to turn attention from the impact of science on science (measured through citations) to the impact of science on society. Advocates imply that the altmetric audience is demographically different from the citing audience for the object. Measuring the audience on social media, however, is not quite as straightforward as measuring a citing audience. Active signals include those who demonstrate explicit interaction with the object (e.g., through tweeting and retweeting). Passive signals are indicated by those to whom the object is implicitly disseminated (e.g., subscribers to the New York Times and followers on Twitter). Following these patterns of dissemination and interaction allows scholars to investigate the diversity of the social media audience. Altmetric aggregators have provided specialized indicators to investigate these effects: for example, the platform ImpactStory will tell you how visible your work has been in the Global South, compared to other scholars on the platform; Altmetric.com provides a similar geographic outlay of the attention to a specific article. In doing so, these sources work to incentivize outreach activities in ways that citation indicators have not traditionally done. Despite these initiatives, it has been demonstrated that altmetrics tend to replicate preexisting networks of scholarly influence and inequalities in science. Most of the data found in altmetric aggregators are retrieved from two platforms: social reference manager Mendeley and microblogging platform Twitter. Mendeley is used largely by graduate students. High volume science tweeters tend to be highly educated individuals from North America and Europe, who favor publications from these continents. Top-followed scientists on Twitter are dominated by science popularizers, men, and those in STEM fields, and tweeting networks tend to reinforce disciplinary boundaries. These findings urge caution for the interpretation of altmetrics as indicators of broader impact. However, we argue that broader impact is not a singular concept with a corresponding indicator. Broader impact can be measured in terms of increased diversity of audience, but it can also be measured in terms of the increased diversity of the research that is disseminated. Broader impacts should not be conceived only as a distinction of the audience which receives the work, but the broadening of the scientific voices which are disseminated and garner attention. Although altmetrics have been well investigated according to audience, there has been less emphasis on evaluating the authorship of the work that receives attention on social media platforms. As a young OA journal, ACS Central Science provides a unique case study of the potential amplifications or disparities that can be revealed when using certain indicators. For example, research has demonstrated consistent disparities in terms of citation received by female-authored papers. Do such disparities hold true in terms of tweets rather than citations? That is, do certain indicators favor different types of authors? And does OA mitigate or amplify these disparities? As an exploratory analysis, we compared ACS Central Science with a number of other journals: large and established chemistry journals (Journal of the American Chemical Society and RSC Advances), high-impact generalist journals (Nature and Science), and their chemistry (Nature Chemistry) and OA (Science Advances, Nature Communications, and Scientif ic Reports) offspring. We focus on gender, using the algorithm developed in Larivière et al. to assign a proxy for gender based on name. As noted, citation disparities by gender have been demonstrated across fields. This trend is reinforced in the citations to work published from 2015 to the present in the