How well developed are Altmetrics? Cross-disciplinary analysis of the presence of 'alternative metrics' in scientific publications

In this paper an analysis of the presence and possibilities of altmetrics for bibliometric and performance analysis is carried out. Using the web based tool Impact Story, we have collected metrics for 20,000 random publications from the Web of Science. We studied the presence and frequency of altmetrics in the set of publications, across fields, document types and also through the years. The main result of the study is that less than 50% of the publications have some kind of altmetrics. The source that provides most metrics is Mendeley, with metrics on readerships for around 37% of all the publications studied. Other sources only provide marginal information. Possibilities and limitations of these indicators are discussed and future research lines are outlined. We also assessed the accuracy of the data retrieved through Impact Story by focusing on the analysis of the accuracy of data from Mendeley; in a follow up study, the accuracy and validity of other data sources not included here will be assessed.