  Measures for research activity and impact have become an integral ingredient
in the assessment of a wide range of entities (individual researchers,
organizations, instruments, regions, disciplines). Traditional bibliometric
indicators, like publication and citation based indicators, provide an
essential part of this picture, but cannot describe the complete picture. Since
reading scholarly publications is an essential part of the research life cycle,
it is only natural to introduce measures for this activity in attempts to
quantify the efficiency, productivity and impact of an entity. Citations and
reads are significantly different signals, so taken together, they provide a
more complete picture of research activity. Most scholarly publications are now
accessed online, making the study of reads and their patterns possible.
Click-stream logs allow us to follow information access by the entire research
community, real-time. Publication and citation datasets just reflect activity
by authors. In addition, download statistics will help us identify publications
with significant impact, but which do not attract many citations. Click-stream
signals are arguably more complex than, say, citation signals. For one, they
are a superposition of different classes of readers. Systematic downloads by
crawlers also contaminate the signal, as does browsing behavior. We discuss the
complexities associated with clickstream data and how, with proper filtering,
statistically significant relations and conclusions can be inferred from
download statistics. We describe how download statistics can be used to
describe research activity at different levels of aggregation, ranging from
organizations to countries. These statistics show a correlation with
socio-economic indicators. A comparison will be made with traditional
bibliometric indicators. We will argue that astronomy is representative of more
general trends.
