Abstract
The study of temporal trends in altmetrics is under-developed, and this multi-year observation study addresses some of the deficits in our understanding of altmetric behaviour over time. The attention surrounding research outputs, as partially captured by altmetrics, or alternative metrics, constitutes many varied forms of data. Over the years 2008-2013, a set of 7739 papers were sampled on six occasions. Five altmetric data sources were recorded (Twitter, Mendeley, News, Blogs and Policy) and analysed for temporal trends, with particular attention being paid to their Open Access status and discipline. Twitter attention both starts and ends quickly. Mendeley readers accumulate quickly, and continue to grow over the following years. News and blog attention is quick to start, although news attention persists over a longer timeframe. Citations in policy documents are slow to start, and are observed to be growing over a decade after publication. Over time, growth in Twitter activity is confirmed, alongside an apparent decline in blogging attention. Mendeley usage is observed to grow, but shows signs of recent decline. Policy attention is identified as the slowest form of impact studied by altmetrics, and one that strongly favours the Humanities and Social Sciences. The Open Access Altmetrics Advantage is seen to emerge and evolve over time, with each attention source showing different trends. The existence of late-emergent attention in all attention sources is confirmed.