@article{thelwall2013altmetrics, abstract = {

Altmetric measurements derived from the social web are increasingly advocated and used as early indicators of article impact and usefulness. Nevertheless, there is a lack of systematic scientific evidence that altmetrics are valid proxies of either impact or utility although a few case studies have reported medium correlations between specific altmetrics and citation rates for individual journals or fields. To fill this gap, this study compares 11 altmetrics with Web of Science citations for 76 to 208,739 PubMed articles with at least one altmetric mention in each case and up to 1,891 journals per metric. It also introduces a simple sign test to overcome biases caused by different citation and usage windows. Statistically significant associations were found between higher metric scores and higher citations for articles with positive altmetric scores in all cases with sufficient evidence (Twitter, Facebook wall posts, research highlights, blogs, mainstream media and forums) except perhaps for Google+ posts. Evidence was insufficient for LinkedIn, Pinterest, question and answer sites, and Reddit, and no conclusions should be drawn about articles with zero altmetric scores or the strength of any correlation between altmetrics and citations. Nevertheless, comparisons between citations and metric values for articles published at different times, even within the same year, can remove or reverse this association and so publishers and scientometricians should consider the effect of time when using altmetrics to rank articles. Finally, the coverage of all the altmetrics except for Twitter seems to be low and so it is not clear if they are prevalent enough to be useful in practice.

}, author = {Thelwall, Mike and Haustein, Stefanie and Larivière, Vincent and Sugimoto, Cassidy R.}, doi = {10.1371/journal.pone.0064841}, interhash = {e8b290200bf83fcd1720e59253febd92}, intrahash = {cefe270b61c929ee0fff81d36cedf87a}, journal = {PLoS ONE}, month = {05}, number = 5, pages = {e64841}, publisher = {Public Library of Science}, title = {Do Altmetrics Work? Twitter and Ten Other Social Web Services}, url = {http://dx.doi.org/10.1371%2Fjournal.pone.0064841}, volume = 8, year = 2013 } @misc{priem2012altmetrics, abstract = {In growing numbers, scholars are integrating social media tools like blogs, Twitter, and Mendeley into their professional communications. The online, public nature of these tools exposes and reifies scholarly processes once hidden and ephemeral. Metrics based on this activities could inform broader, faster measures of impact, complementing traditional citation metrics. This study explores the properties of these social media-based metrics or "altmetrics", sampling 24,331 articles published by the Public Library of Science. We find that that different indicators vary greatly in activity. Around 5% of sampled articles are cited in Wikipedia, while close to 80% have been included in at least one Mendeley library. There is, however, an encouraging diversity; a quarter of articles have nonzero data from five or more different sources. Correlation and factor analysis suggest citation and altmetrics indicators track related but distinct impacts, with neither able to describe the complete picture of scholarly use alone. There are moderate correlations between Mendeley and Web of Science citation, but many altmetric indicators seem to measure impact mostly orthogonal to citation. Articles cluster in ways that suggest five different impact "flavors", capturing impacts of different types on different audiences; for instance, some articles may be heavily read and saved by scholars but seldom cited. Together, these findings encourage more research into altmetrics as complements to traditional citation measures.}, author = {Priem, Jason and Piwowar, Heather A. and Hemminger, Bradley M.}, interhash = {629744ad15197eedde33f8444c3e8e01}, intrahash = {e22613ac29fd25f21430739a4c3e001c}, note = {cite arxiv:1203.4745v1Comment: 5 tables, 13 figures}, title = {Altmetrics in the wild: Using social media to explore scholarly impact}, url = {http://arxiv.org/abs/1203.4745}, year = 2012 }