87. However, Katz and Martin [1997] argued that collaboration and co-authorship are not
interchangeable and that co-authorship can only be a partial indicator of collaborative activity.
For example, it is possible to conceive of two researchers collaborating closely but publishing
their results separately, or the instance when two researchers did not collaborate during the
research phase but decided to pool their results in a jointly authored paper. In fact about 5-8%
of SCI papers list more institutions that authors suggesting that at least one author resides at
two or more institutions [Katz, 1993]. This could indicate that there may be a formal or informal
agreement between two institutions to collaborate by sharing a researcher. For these reasons,
bibliometric measures can only be a partial indicator of collaborative activity.