Main path analysis

It has since become an effective technique for mapping technological trajectories, exploring scientific knowledge flows, and conducting literature reviews.

Academic research related to main path analysis saw a fast growing since 2007.

A list of academic articles that introduce, explain, apply, modify, or extend the method originated in Hummon and Doreian[1] can be found here.

Nevertheless, there are issues not broadly discussed in applying the method, including the handling of citation data, choosing a proper traversal weight scheme, search options, and interpretation of the resulting paths.

In a citation network, the nodes represent the documents such as academic articles, patents, or legal cases.

Citation networks are by nature directed because the two nodes on the opposite end of a link are not symmetrical in their roles.

Citation network is also by nature acyclic, which means that a node can never chain back to itself if one moves along the links following their direction.

The SPC value for the link (B, D) is 5 because five paths (B-D-F-H-K, B-D-F-I-L, B-D-F-I-M-N, B-D-I-L, and B-D-I-M-N) traverse through it.

They are: B-D-F-H-K, B-D-F-I-L, B-D-F-I-M-N, D-F-H-K, D-F-I-L, and D-F-I-M-N, noting that all the paths begin either from the ancestor of D, which is B, and D itself.

Figure 4 shows the local main paths that are obtained based on SPC.

Noticing that when the search reaches the node I, two outgoing links have the same SPC values thus producing two paths afterward.

The concept of global search is similar to the critical path method in project scheduling.

The global main paths of the sample citation network based on SPC is presented in Figure 5.

When the number of key-route increases to a certain point the search returns the whole citation network.

In both main paths the number of key-route is set to 1, i.e., doing the search base on only the top links.

More recent applications include fullerenes,[4] nanotubes,[4] data envelopment analysis,[2][13][14] supply chain management,[15] corporate social responsibility,[16] IT outsourcing,[17] medical tourism,[18] etc.

Verspagen (2007)[3] and Mina (2007)[19] are the two early works that apply main path analysis to the patent data.

The new feature allows for local and global search passing through vertices defined by a cluster.

Main path analysis uncovers the most significant paths, or citation chains, in a citation network. The figure shows the global key-route main paths (in red) for a sample citation network (based on search path count and at key-route 1).
Figure 1. SPC values for a sample citation network
Figure 2. SPLC values for a sample citation network
Figure 3. SPNP values for a sample citation network
Figure 4. Local main paths in a sample citation network
Figure 5. Global main paths in a sample citation network
Figure 6. Local key-route main paths in a sample citation network
Figure 7. Global key-route main paths in a sample citation network