1. It was concluded that the data collection and field delineation approach with multiple
databases was successful in addressing the problems of low recall concerning the early
time periods with the lexical query approach, and in comparison with the earlier
review literature the early timeslice of 1985-1994 seemed representative, however,
some further procedures could be tested to improve recall during this period.
Especially with respect to the indexing delays of the core journals in WoS it would
seem appropriate to try to increase recall in future studies. The time period of 1985-
2009 was chosen on the basis of retrieved articles, with an improved recall the
longitudinal perspective could possibly be stretched further back. In the citation based
extension phase I used direct citations to identify potentially similar articles by which
the core set could be expanded. In order to increase the recall of articles potentially
similar to the core set of articles, the rationale of bibliographic coupling or lexical
coupling might be a more suitable choice. However, there is – to my knowledge – a
limitation to this approach. While citation based extension based on direct citations are
supported by WoS through the Create citation report function, the coupling strategies