Chapter discussion

This chapter set out to adapt five models to include disciplinary and interdisciplinary authors. These models were then tested to see if they held and to establish whether there was a difference between disciplinary and interdisciplinary nodes. Observing such a difference would have served as the foundation to understanding why the differences exist and in turn help develop a model that can identify individuals who enable and sustain IDR.

Two hypotheses were designed to establish this. Hypothesis 7.1 was designed to establish whether the model held. Hypothesis 7.2 was designed to establish how interdisciplinary authors differed from disciplinary authors.

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Hypothesis 7.1 found that all the models had trends with the concepts. The Eigenvector/PageRank model was rejected, although as literature had mixed findings, this was not altogether unexpected. The strength of weak ties models was rejected, and was therefore not considered further as it was not node centric.

This helped establish that many of the models were in fact applicable to co-authorship networks and the wider collaboration networks that they represent. That these were also applicable when hard boundaries were drawn around a research organisation represents a minor contribution to knowledge.

Having established that these models held (with the exception of the strength of weak ties), it was possible to determine whether any differences between disciplinary and interdisciplinary nodes existed. Hypothesis 7.2 was designed to establish this.

With the exception of the PageRank content-based disciplines, Hypothesis 7.2 was rejected across all the models. This means that with the exception of the PageRank content-based disciplines, no differences between disciplinary and interdisciplinary authors were found.

Delving further into the PageRank content-based disciplines provided many questions. The disciplinary and interdisciplinary had positive trends with the impact factor when the impact factor was not normalised. This may be an indication that this was driven by hubs of excellence. However, do these hubs consist of a mix of disciplinary and interdisciplinary people, and if so in which discipline definition? The fact that interdisciplinary authors in content-based disciplines provided greater benefit to interdisciplinary people is an indication that organic interdisciplinarity hubs provide the greatest benefits. These could be an indication of highly heterogeneous knowledge, but with low barriers (e.g. Mechanical Engineering staff from different parts of the department working on a single problem – this provides all the benefits of IDR, but with fewer of the drawbacks). However, the question as to why this is not seen in either the degree or betweenness models is not explainable with the current research.

A study to explain why this could be occurring needs to be conducted.

Furthermore, that a difference was only discovered in one of the models very specifically does question the credibility.

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Contribution to knowledge:

In testing the overall chapter hypothesis: “SNA models show that there are differences between disciplinary and interdisciplinary authors.” By virtue of Hypothesis 7.2 being rejected in almost all cases, the chapter Hypothesis is rejected. This has important implications as it suggests that the premise that there are disciplinary and interdisciplinary archetypes is refuted. The represents an original contribution to knowledge, that outlines part of the reason why traditional networks analysis is unsuitable to investigate IDR.

To overcome this weakness, it is necessary to shed the disciplinary and interdisciplinary authors paradigm, and to consider different types of links. This would reduce the overall number of assumptions in the analysis and accepts that there are no such thing as interdisciplinary authors, but just interdisciplinary links. It would be a more realistic representation of the reality of the situation (i.e. a person is classified to a particular discipline, and can be connected to any other individuals in any other discipline).

This would require a framework that is able to consider 𝑀2 types of links (𝑀 is the number of disciplines). If this were applied individually to create 𝑀2 networks, then every network would be very sparse, and the networks analysis would be meaningless. It is therefore necessary to create a framework that is adequately able to relate each of these links to each other, even though they are not equivalent.

Such a framework falls under the field of multilayer networks analysis. This was deemed to be the only reliable approach that can minimise the number of assumptions and provide a more effective way of analysing IDR through the use SNA.

This recommendation can be considered a contribution to knowledge, as it advances the knowledge of SNA seeking to investigate IDR.

Furthermore, as the models were correlated to the impact factor, but this provides no distinction between disciplinary and interdisciplinary outputs. This compounded with the difficulty in measuring IDR, makes this study and measure unsuitable. The future degree is therefore a better operational definition for enabling and sustaining IDR as it provides a direct measure of whether an individual collaborates more (enabling) and if this can show to hold predictively (sustaining) the research aim can be achieved.

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7.9. Chapter summary

This chapter assumed that disciplinary and interdisciplinary authors existed as archetypes of authors. This work tried to establish if there was any difference between these two using SNA. Five different models were adapted to test this, and although the models themselves were corroborated (with the exception of the strength of weak ties), only a single case where differences occurred could be found.

Therefore, the archetypes concept is rejected (the case where there was a statistically significant trend is deemed insufficient). Furthermore, without distinguishing between interdisciplinary impact factors and disciplinary impact factors, this work correlates equal output. It is therefore necessary to develop a framework that can address these issues. A multilayer perspective could address these issues whilst simultaneously improving analytical resolution by considering the context of the IDR collaborations (e.g. Physics-Chemistry pair as the context between two collaborators from each discipline).

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Chapter 8: Multilayer Networks Review and framework