Can “hot spots” in the sciences be mapped using the dynamics of aggregated journal–journal citation Relations?

Using 3 years of the Journal Citation Reports (2011, 2012, and 2013), indicators of transitions in 2012 (between 2011 and 2013) were studied using methodologies based on entropy statistics. Changes can be indicated at the level of journals using the margin totals of entropy production along the row or column vectors, but also at the level of links among journals by importing the transition matrices into network analysis and visualization programs (and using community‐finding algorithms). Seventy‐four journals were flagged in terms of discontinuous changes in their citations, but 3,114 journals were involved in “hot” links. Most of these links are embedded in a main component; 78 clusters (containing 172 journals) were flagged as potential “hot spots” emerging at the network level. An additional finding was that PLoS ONE introduced a new communication dynamic into the database. The limitations of the methodology were elaborated using an example. The results of the study indicate where developments in the citation dynamics can be considered as significantly unexpected. This can be used as heuristic information, but what a “hot spot” in terms of the entropy statistics of aggregated citation relations means substantively can be expected to vary from case to case.