A critical review on altmetrics: can we measure the social impact factor?

Altmetrics measure the digital attention received by a research output. They allow us to gauge the immediate social impact of an article by taking real-time measurements of how it circulates in the Internet. While there are several companies offering attention scores, the most extensive are Altmetric.com (Altmetric Attention Score-AAS) and Plum X (Plum Print). As this is an emerging topic, many medical specialities have tried to establish if there is a relationship between an article's altmetric data and the citations it subsequently receives. The results have varied depending on the research field. In radiology, the social network most used is Twitter and the subspeciality with the highest AAS is neuroimaging. This article will review the process involved from the start when an article is published through to finally obtaining its altmetric score. It will also address the relationship between altmetrics and more traditional approaches focusing on citations in radiology and will discuss the advantages and limitations of these new impact indicators.