We first consider the general characteristics and resilience assessment of the collaboration networks of these universities. Then, we examine in more detail the network characteristics and resilience measures of each of the four universities, as well as analyze the dynamics of these characteristics over time. The collaboration networks were constructed based on publications covering the period from 2018 to 15 September 2025, which makes it possible to trace changes over nearly a full decade. For AITU, the analysis was carried out using publications starting from 2019, the year of its founding, up to 15 September 2025. The choice of this time interval was motivated by the need to ensure comparable conditions across the universities: since AITU is the youngest among the selected institutions, starting from 2019 guarantees that the results are representative and do not include periods when the university was not yet operational. This approach enables a correct comparison of the indicators of the four universities within a common time frame while accounting for the specifics of different stages of their development.
To collect the data, the open database OpenAlex and the pyalex library were used, providing access to the platform’s API. Each university in OpenAlex has a unique Research Organization Registry (ROR) identifier, which is used to link author affiliations to specific institutions. Within the scope of this study, the ROR identifiers of the universities were determined manually based on the official organizational profiles in the ROR system. Data retrieval was performed directly using the query Works().filter(authorships={“institutions”: {“ror”: ror}}).paginate(per_page=200, n_max=None), which returned all publications in which at least one author was affiliated with the selected university. The pagination method allowed sequential retrieval of all results without a limit on their number, ensuring complete coverage of university publications over the entire observation period. The data obtained were stored in NumPy format for subsequent analysis of the number of unique authors, publications, and indexing indicators.
Additional analysis of indexing revealed that for AITU and NU, approximately 42–46% of publications are indexed in the international scientometric databases Scopus and Web of Science, whereas for US and STU, this figure reaches 65–75%. This difference can be partly explained by the specifics of Kazakhstan’s publication landscape, where a significant portion of research is published in national journals and proceedings that hold professional status but are not always included in international scientometric databases.
At the same time, the use of the OpenAlex source considerably broadens publication coverage, as it accounts not only for materials indexed in Scopus or Web of Science but also for works published in local or specialized journals, conference proceedings, and open-access platforms. This provides a more comprehensive representation of the universities’ research activity, especially in contexts where local platforms play an important role in developing scientific schools and supporting national research priorities.
Thus, the lower percentage of publications indexed in international databases for AITU and NU does not necessarily indicate lower research quality but rather reflects differences in publication strategies and the orientation of part of the research output toward the internal academic space.
4.2. Comparative Analysis of Network Characteristics of AITU, NU, STU and US
The comparative assessment of collaboration structures at AITU, NU, STU, and US reveals how differences in institutional scale, research intensity, and disciplinary diversification shape the internal cohesion of scientific networks. Despite sharing the general features typical of academic collaboration systems (sparse connectivity and a high tendency for local clustering), these four universities differ significantly in both size and the density of their internal relationships.
Among them, STU demonstrates the most expansive and mature scientific ecosystem, encompassing eight thousand three hundred fifty-nine authors connected through 49,820 co-authorship links over the 2019–2025 period. Nazarbayev University maintains a mid-sized yet highly structured community with three thousand eight hundred sixty-twoauthors and 13,363 connections, while AITU, though smaller with three thousand two hundred thirty-nine authors and 12,549 links, shows clear signs of dynamic growth and progressive consolidation. The University of Suffolk, by contrast, represents a compact network of five hundred seventy-nine authors and nine hundred seventeen edges, reflecting the more localized and project-based character of its collaborations.
When examining interaction intensity, the average number of collaborators per researcher varies widely: from 11.92 at STU to 7.75 at AITU, 6.92 at NU, and only 3.17 at US. These disparities highlight the more complex intra-institutional connectivity in the Asian universities compared with the European one. However, the overall network density remains low (ranging from 0.0014 to 0.0055), consistent with the general sparsity of co-authorship graphs, where new links typically emerge only within specialized subfields or shared projects.
The degree of local cohesion, reflected in clustering coefficients, further clarifies these structural contrasts. The clustering coefficient remains remarkably similar for AITU, NU, and STU (each around 0.61–0.62), pointing to a pronounced presence of small, tightly connected research groups. In the case of STU, this parameter increased from 0.59 in 2019 to 0.63 in 2025, which indicates gradual consolidation of collaboration networks and a strengthening of internal group boundaries. Conversely, the university exhibits a substantially lower clustering coefficient (approximately 0.40), signifying fragmentation and weaker interconnection between local clusters. This reduced cohesion reflects its dependence on individual research initiatives rather than long-term institutional collaboration programs.
The level of integration within each network can also be evaluated through the largest connected component (LCC), the portion of researchers linked into a single, uninterrupted collaboration structure. Here, too, the hierarchy is consistent with other measures: STU’s LCC includes seven thousand seventy-four authors, or roughly 84.6% of its entire network; NU retains a similar proportion at 81% (three thousand one hundred thirty-one authors); AITU connects about half of its researchers (one thousand six hundred ten, or 50%); while US remains the most fragmented, with only one hundred twenty-seven authors (≈22%) belonging to its core. Notably, AITU’s share of the LCC rose markedly after 2022, reaching 45.1% by 2024, which confirms an ongoing process of consolidation and institutional networking.
Beyond these core structural metrics, the Edge Jaccard Index, which tracks the renewal of co-authorship ties between consecutive time windows, reveals how stable or dynamic these relationships are. In AITU, the index remains very low (0.01036), showing that only about 1% of collaboration links persist from year to year. A sign of rapid reconfiguration and fluid team formation. For STU (0.0377) and NU (0.035), the values are roughly three times higher, denoting more stable research clusters and longer-term partnerships. Meanwhile, US maintains a moderate figure (0.0243), implying a mix of stability and turnover in its partnerships.
Finally, the organization of communities within each network, as captured by modularity, indicates different stages of scientific ecosystem development. AITU demonstrates a relatively low modularity (0.309), which reflects the ongoing integration of previously isolated research groups into larger interdisciplinary clusters. NU, by contrast, maintains a higher modularity value of about 0.902, corresponding to the coexistence of several well-defined and internally cohesive research hubs. STU, with modularity fluctuating near 0.887–0.888, exhibits a balanced structure that supports both strong local ties and effective intergroup interaction. US, with modularity around 0.773, shows a greater degree of fragmentation, typical for smaller, project-driven academic environments.
Taking together, these indicators reveal a clear developmental hierarchy. STU stands as a large-scale, cohesive, and steadily consolidating research network. NU combines moderate size with strong integration and distinct community organization. AITU continues to expand dynamically, marked by rapid tie renewal and progressive strengthening of its collaborative core. US remains limited in scope and density, exhibiting the structural traits of an emerging network rather than a fully institutionalized research ecosystem.
These differences indicate that the institutional maturity and the scale of interdisciplinary research directly influence network compactness and clustering. STU’s high values correspond to the model of a large, stable scientific ecosystem, while AITU’s dynamic growth suggests an emerging but increasingly connected research environment. NU’s metrics emphasize a balance between local and global cohesion, and US’s low clustering underlines its dispersed collaboration patterns and dependence on individual leaders (see
Figure 2).
The share of nodes forming the largest connected component (LCC) serves as a key indicator of the integration level within each institution. For instance,
Figure 3 illustrates that in 2024, the proportion of authors included in the LCC exceeds 80% for STU and NU, showing strong network coherence. AITU’s LCC integrates roughly half of all researchers, revealing steady consolidation, while in US the LCC rarely surpasses 20%, highlighting a highly fragmented structure. Such disparity underlines the varying ability of these universities to maintain a continuous flow of information and cooperation.
Temporal analysis indicates that both NU and STU preserve a consistent LCC ratio across years, confirming resilient internal communication frameworks. AITU demonstrates a notable rise in this indicator after 2022, which corresponds to the rapid expansion of interdisciplinary teams. In contrast, the US network remains sparse, with numerous small, disconnected components, confirming a lack of systematic collaboration.
Modularity coefficients further substantiate these findings. STU’s modularity fluctuates between 0.3 and 0.4, suggesting a well-balanced division into thematic clusters with strong intra-group and moderate inter-group ties. NU’s modularity is slightly higher, reflecting the coexistence of several dominant research centers. AITU’s modularity decreases over time, showing the gradual unification of its previously isolated teams. For US, modularity remains near 0.6, typical of highly fragmented networks with small, isolated communities.
The assortativity coefficient reflects the degree of homophily—the preference of authors to collaborate with others who have similar levels of productivity or connectivity. Comparative dynamics reveal a distinct typology across the four universities.
Figure 4 presents the trajectories of assortativity change, demonstrating that AITU initially exhibits high positive assortativity (≈0.9 in 2020–2021), indicating intensive cooperation within homogeneous groups. After 2022, this value decreases sharply and approaches zero, meaning that the network becomes more diverse and cross-collaborative.
NU’s assortativity remains slightly negative (−0.05 to −0.1), implying a heterogeneous structure where central authors frequently connect with peripheral participants, facilitating information diffusion. STU maintains consistently positive values (≈0.3–0.7), confirming a mature, internally coherent collaboration system. US exhibits strong fluctuations, from negative (−0.4) to high positive (≈0.8) values, which reveals unstable group formation and dependence on temporary project-based alliances.
Temporal patterns across all four universities show that assortativity transitions from homophilic to neutral or heterophilic tendencies as networks expand and diversify. In early developmental stages, most institutions demonstrate clustering around strong local leaders, whereas in later years collaboration becomes more cross-sectional. This process aligns with the theory of network maturation, where the growing number of interdisciplinary connections diminishes assortativity but strengthens global integration.
To evaluate structural stability, targeted node removal simulations were conducted, focusing on nodes ranked by betweenness centrality.
Figure 5 visualizes the comparative resilience of the four networks. The results clearly distinguish four patterns of network resilience: STU displays the highest resilience, NU maintains moderate stability, AITU shows improving resilience, and US collapses under minimal perturbations.
Specifically, STU remains highly resistant: even after removing 50% of central nodes, its largest component still includes more than 3900 authors. NU retains approximately 1500 connected researchers after similar removal, while AITU’s LCC remains at about 700 nodes following substantial deletions. In contrast, the US network disintegrates rapidly. After eliminating merely 10% of high-betweenness nodes, and connectivity nearly vanishes. Random node-removal experiments validate these observations: for STU and NU, fragmentation begins beyond the 20% threshold, while for AITU and US, disintegration starts much earlier.
These results demonstrate that network resilience strongly depends on the balance between clustering and degree centralization. Networks with moderate centralization and strong clustering are more resilient to targeted attacks, whereas sparse and centralized structures (like US) collapse easily.
To assess the resilience of the collaboration network, a simulation-based approach was applied that considered two node-removal scenarios: random and targeted. Both scenarios were implemented for the empirical AITU co-authorship network as well as for a baseline Erdős–Rényi (ER) model with corresponding parameters (number of nodes and average edge density). In the random scenario, nodes were removed with equal probability. For each removal fraction, multiple simulations were conducted, and the results were averaged to reduce random fluctuations. The extraction procedure was performed ten times for each university. The resulting data were then averaged using the simple arithmetic mean of the obtained indicators. This scenario reflects nonspecific losses of collaboration participants, such as staff turnover or temporary research interruptions. In the targeted scenario, nodes were removed in descending order of centrality values (degree or betweenness), thereby simulating the loss of key researchers who act as intermediaries between different groups of the scientific network. At each stage, the size of the largest connected component was evaluated relative to the initial number of nodes. This ratio was used as the primary indicator of network integrity preservation during progressive node removal.
In the case of random removal, the behavior of the empirical network is expected to approach that of the ER model, with the differences indicating specific features of its organization, particularly the presence of clustering. If the decline in the real network occurs faster than in the ER model, this points to dependence on a narrow circle of highly influential authors. Conversely, if the decline is slower, it suggests a more evenly distributed influence and increased network resilience.
The comparison of empirical and model results enables the drawing of conclusions about the resilience of the scientific ecosystem at AITU. In particular, it allows for the assessment of whether researchers’ collaboration is stable under conditions of random losses or critically dependent on a small group of leading scholars. The obtained results have practical significance for the development of institutional strategies aimed at strengthening horizontal ties, expanding intergroup collaborations, and ensuring the long-term stability of the scientific network.
Figure 6 presents the results of node removal simulations for the AITU collaboration network compared with the baseline ER model. The
x-axis represents the fraction of removed nodes, while the
y-axis shows the relative size of the largest connected component (Largest Component Ratio, G/N). The blue curve illustrates that, under random node removal, the network retains its relative integrity even with gradual losses. The decline of the largest component is progressive, indicating the presence of alternative collaboration pathways and a certain level of redundancy in connections. Comparison with the green curve (ER model) shows that the empirical network collapses faster than a random graph of similar density, indicating greater structural resilience due to clustering and an uneven distribution of ties. The most striking is the red curve, corresponding to the removal of nodes with the highest degree centrality values. After the removal of just 10–15% of the most central researchers, the largest component almost disappears. This indicates a critical dependence of the network on a limited circle of key authors who ensure integration between different research groups. For comparison, the purple curve (ER model) demonstrates much higher resilience even under targeted node removal. The vertical dashed line represents the theoretical threshold for random removal in the ER model.
The results obtained demonstrate a substantial difference between the random and targeted scenarios. While the network is relatively resilient to random losses, it proves to be highly vulnerable to the removal of nodes with the highest centrality. This highlights the crucial integrative role of AITU’s leading researchers and, at the same time, underscores the risk of fragmentation of the scientific ecosystem in the event of their loss. From a practical perspective, the results point to the need to develop a more balanced collaboration structure and to strengthen connections between research groups.
The analysis made it possible to identify two key threshold values for the targeted removal scenario of nodes with the highest centrality scores. First, it was established that the sharpest decline in network integrity occurs at a removal fraction of approximately 13%. At this point, the largest connected component experiences the greatest loss, indicating a high concentration of integrative roles within a relatively narrow group of researchers. The removal of even a small share of these actors leads to rapid fragmentation of the network and the loss of its global connectivity. Second, a critical threshold of complete network disintegration was identified at a removal fraction of about 73%. At this level, the network loses the ability to sustain a significantly sized largest component, and the remaining substructures preserve only local interactions. Thus, even under gradual removal of the most central nodes, the global structure ultimately collapses only after reaching relatively high levels of removal.
The results obtained demonstrate that the AITU collaboration network is highly sensitive to selective losses of key participants. The greatest risk is associated not with the overall scale of losses, but with their specificity. Even a small fraction of highly influential researchers being removed leads to a significant decline in network integration. At the same time, the persistence of residual components that maintain local resilience up to the threshold of over 70% indicates the formation of stable subgroups and research clusters capable of functioning independently of the global structure.
Figure 7 compares the scenarios of random and targeted node removal in the real NU network and its random counterpart based on the ER model. In the case of random removal, the NU network retains relative resilience. For the random ER network, a similar smooth dynamic is observed, although the critical threshold is reached later, which is consistent with the theoretically expected value (r ≈ 0.85). In contrast, targeted removal of high-degree nodes shows a sharp decline in the size of the largest component of the NU collaboration network after the removal of only about 10–15% of key researchers. In the random ER network, targeted removal has a much less pronounced impact, highlighting the specific resilience of NU as a real scientific community.
As shown in
Figure 7, targeted removal of central nodes leads to a sharp collapse of the resilience assessment already at the early stages. The global structure of the network is almost completely destroyed after the loss of the first key researchers. In the case of random losses, the largest component decreases gradually, retaining a significant share of participants even after the removal of one-tenth of the network, while critical reduction occurs only after more than fifteen percent of the nodes have been removed.
As shown in
Figure 8, in the case of random node removal (blue curve), the STU scientific collaboration network demonstrates a high level of resilience. Even after removing half of the nodes, approximately 30% of the initial collaboration core remains intact. Unlike other young universities, where a sharp decline occurred after removing just 10–15% of the most central nodes, the STU network exhibits a more gradual decrease: a significant portion of its structural integrity is preserved up to a threshold of approximately r ≈ 0.2, followed by a smooth transition to the fragmentation stage. This behavior suggests a reduced reliance on a select group of leading researchers. The empirical STU network is also more robust to random failures than its ER model counterpart. Therefore, the STU network demonstrates high resilience, maintaining its functional integrity even after substantial structural losses.
Based on the analysis, as shown in
Figure 9, it can be concluded that the US’s scientific collaboration network is highly vulnerable to structural disruptions. Even a minor loss of central nodes leads to an almost immediate breakdown of global connectivity and fragmentation of the system into isolated local clusters.
Each simulation included fifty points corresponding to the sequential removal of 1 to 50% of nodes in the researcher network. For each point, the variance of the results was calculated based on ten independent experiments. The obtained values reflect the stability of the network structure under random node removal, allowing for the assessment of the degree of variability in the system’s response to destructive influences. Subsequently, for each university, the average variance across all simulation points was calculated. The results revealed significant differences among the universities. In particular, the variances are 0.01232 for AITU, 0.02998 for US, 0.00372 for NU, and 0.00257 for STU. As can be seen, for NU and STU, the variance is approximately an order of magnitude lower than for AITU and US, indicating higher stability of the obtained results and a more homogeneous network response to the reduction in the number of active nodes. As can be seen from the results, for NU and STU, the variance is an order of magnitude lower than for AITU and US, indicating higher stability of the obtained results and a more uniform network reaction to the decrease in the number of active nodes. One possible explanation for this difference may be the varying size of the initial samples: for example, in the case of US, the number of publications and authors is significantly smaller, which increases the model’s sensitivity to random removals. At the same time, this factor is not the only one. A significant role may also be played by the dynamics of development of young universities, which are characterized by an unstable structure of scientific collaboration, a limited number of stable inter-institutional links, and high variability in the composition of active authors. Thus, higher variance values for AITU and US can be interpreted as a manifestation of greater structural instability of their scientific networks compared to NU and STU.
To ensure the reliability of the obtained results, an additional experiment was conducted to calculate the characteristics of the scientific collaboration networks for one of the universities presented in the study. STU was taken as the basis. In this case, only the data indexed in the Web of Science were considered. The following network characteristics were obtained for the period 2019–2025: number of nodes—7768, number of edges—47,764, density—0.0015, average degree—12.2976, average clustering—0.6271, size of the largest connected component—6681, Edge Jaccard Index—0.387.
The analysis of the obtained results (
Figure 10,
Figure 11,
Figure 12 and
Figure 13) showed that, despite the decrease in the absolute values of the size of the largest connected component after restricting the sample to data from the Web of Science database only, the overall behavior of the functions remained practically unchanged. To quantitatively assess the similarity between the results obtained from the complete dataset and those derived from the Web of Science data, Pearson correlation coefficients were calculated between the corresponding curves for different scenarios.
For Random Removal, the Pearson correlation coefficient is 0.97; for Targeted Removal (Degree)—0.96; for Random Removal (ER)—0.87; and for Targeted Removal (Degree, ER)—1.00. As can be seen, all obtained coefficients exceed 0.85, and in most cases approach 1.0, indicating a very high correlation between the curves. This means that the removal of part of the data (in particular, restricting the analysis to publications indexed in WoS) did not affect the overall dynamics of network degradation, while the changes mainly concerned only the scale of the indicators. Thus, it can be concluded that using WoS data exclusively does not provide significant analytical advantages but merely reduces the sample size and, accordingly, the scale of the network without altering the fundamental patterns of its structural behavior.