largely isolated from other journals in the network. On the other hand, CACM continues to be a source of information to journals from both the computer science and IS camps, but is no longer an important source of information to the professional/managerial and operations research journal clusters.

Increasing the threshold from 0.10 to 0.15 does not greatly impact the view of CACM’s relationships to other journals, although it does lead to a clearer overall delineation of network relationships (see Figure 3). By combining the information from these three flow diagrams, we infer that the journals giving the highest proportion of their overall citations to CACM in 2003 had the following research foci:

• Software engineering, data management, and computer systems;

• E-commerce;

• Collaboration and group support systems;

• Human-computer interaction;

• IT’s role in society; and

• Emerging areas for IS research and development.

Information flow analysis can also be used to identify which network journals are the most important sources of information for CACM itself. Only two journals (MIS Quarterly and Harvard Business Review) received more than 10% of CACM’s total citations within the network in 2003. Other journals receiving at least 4% of CACM’s network citations include (in descending order) IEEE Computer, Sloan Management Review, Management Science, Information Systems Review, and IEEE Software, all of which are highly respected publications within their respective disciplines.

LEGEND IS CS Mgmt/Prof OR Not classified

Figure 3. Information flow (spring embedding, 0.15 threshold).

Information flow analysis also identifies information sources (journals that receive citations from more journals than they cite) and information sinks (journals that make citations to many different journals, but are not cited by as many in return). Overall, 52 journals were classified as information sources and 67 as information sinks. CACM received the second-highest information-source ranking in the network (net degree of 52,

compared to a net degree of 55 for Harvard Business Review). Overall, CACM cited 49 journals in 2003 and was cited by 101. These scores are obviously highly sensitive to restrictions on reference lists or infrequent publication cycles. Some scores might also be affected by JCR’s practice of truncating most journal-to-journal citation counts less than two.

Prominence measures. An actor’s prominence in a social network can be based on either centrality ( visibility due to “extensive involvement in relations”) or prestige (visibility based on “the extensive relations directed at them”) [ 4]. In a journal citation network, it is more appropriate to assess prominence based on measures of prestige, rather than centrality.

Network actors can exhibit prominence due to having more direct ties with other actors (degree centrality/prestige), shorter path lengths to other actors (closeness centrality/prestige), or structurally advantageous positions between other actors (betweenness centrality/prestige) [ 2]. Degree is a localized measure providing information on an actor’s immediate neighborhood, whereas closeness and betweenness are global measures.

Prominence measures are best interpreted in light of the overall level of network centralization. Centralization measures report a network’s degree of centralization as a percentage of that of a perfectly centralized star network [ 2]. Thus the higher the network centralization, the more closely the network resembles a perfect star network with one central actor, indicating unequal distribution of power (or prestige) within the network. While the centralization of the IS journal network varies depending on the measure used, it tends to be moderate at best (ranging from 21.50% for betweenness measures to 66.45% for degree measures).

Freeman degree prestige is a common method of determining journal rankings, including our normal-