scholarly journals Sensitivity and robustness of comorbidity network analysis

2019 ◽  
Author(s):  
Jason Cory Brunson ◽  
Thomas P. Agresta ◽  
Reinhard C. Laubenbacher
Keyword(s):  
Network Analysis ◽  
Network Structure ◽  
Global Network ◽  
Data Sets ◽  
Multivariate Models ◽  
Occurrence Data ◽  
Level Data ◽  
Pairwise Models ◽  
Global Statistics ◽  
Specific Symptoms

1Summary and KeywordsBackgroundComorbidity network analysis (CNA) is an increasingly popular approach in systems medicine, in which mathematical graphs encode epidemiological correlations (links) between diseases (nodes) inferred from their occurrence in an underlying patient population. A variety of methods have been used to infer properties of the constituent diseases or underlying populations from the network structure, but few have been validated or reproduced.ObjectivesTo test the robustness and sensitivity of several common CNA techniques to the source of population health data and the method of link determination.MethodsWe obtained six sources of aggregated disease co-occurrence data, coded using varied ontologies, most of which were provided by the authors of CNAs. We constructed families of comorbidity networks from these data sets, in which links were determined using a range of statistical thresholds and measures of association. We calculated degree distributions, single-value statistics, and centrality rankings for these networks and evaluated their sensitivity to the source of data and link determination parameters. From two open-access sources of patient-level data, we constructed comorbidity networks using several multivariate models in addition to comparable pairwise models and evaluated differences between correlation estimates and network structure.ResultsGlobal network statistics vary widely depending on the underlying population. Much of this variation is due to network density, which for our six data sets ranged over three orders of magnitude. The statistical threshold for link determination also had strong effects on global statistics, though at any fixed threshold the same patterns distinguished our six populations. The association measure used to quantify comorbid relations had smaller but discernible effects on global structure. Co-occurrence rates estimated using multivariate models were increasingly negative-shifted as models accounted for more effects. However, only associations between the most prevalent disorders were consistent from model to model. Centrality rankings were likewise similar when based on the same dataset using different constructions; but they were difficult to compare, and very different when comparable, between data sets, especially those using different ontologies. The most central disease codes were particular to the underlying populations and were often broad categories, injuries, or non-specific symptoms.ConclusionsCNAs can improve robustness and comparability by accounting for known limitations. In particular, we urge comorbidity network analysts (a) to include, where permissible, disaggregated disease occurrence data to allow more targeted reproduction and comparison of results; (b) to report differences in results obtained using different association measures, including both one of relative risk and one of correlation; (c) when identifying centrally located disorders, to carefully decide the most suitable ontology for this purpose; and, (d) when relevant to the interpretation of results, to compare them to those obtained using a multivariate model.

scholarly journals Sensitivity of comorbidity network analysis

JAMIA Open ◽  
2019 ◽  
Vol 3 (1) ◽  
pp. 94-103 ◽  
Author(s):  
Jason Cory Brunson ◽  
Thomas P Agresta ◽  
Reinhard C Laubenbacher
Keyword(s):  
Network Analysis ◽  
Rank Correlation ◽  
Data Sets ◽  
Theoretic Approach ◽  
Summary Statistics ◽  
Graph Theoretic ◽  
Occurrence Data ◽  
Highly Sensitive ◽  
The Stability ◽  
Low Prevalence

Abstract Objectives Comorbidity network analysis (CNA) is a graph-theoretic approach to systems medicine based on associations revealed from disease co-occurrence data. Researchers have used CNA to explore epidemiological patterns, differentiate populations, characterize disorders, and more; but these techniques have not been comprehensively evaluated. Our objectives were to assess the stability of common CNA techniques. Materials and Methods We obtained seven co-occurrence data sets, most from previous CNAs, coded using several ontologies. We constructed comorbidity networks under various modeling procedures and calculated summary statistics and centrality rankings. We used regression, ordination, and rank correlation to assess these properties’ sensitivity to the source of data and construction parameters. Results Most summary statistics were robust to variation in link determination but somewhere sensitive to the association measure. Some more effectively than others discriminated among networks constructed from different data sets. Centrality rankings, especially among hubs, were somewhat sensitive to link determination and highly sensitive to ontology. As multivariate models incorporated additional effects, comorbid associations among low-prevalence disorders weakened while those between high-prevalence disorders shifted negative. Discussion Pairwise CNA techniques are generally robust, but some analyses are highly sensitive to certain parameters. Multivariate approaches expose additional conceptual and technical limitations to the usual pairwise approach. Conclusion We conclude with a set of recommendations we believe will help CNA researchers improve the robustness of results and the potential of follow-up research.

Foreign Capital and Economic Growth: A Social Network Analysis, 2001–2017

2021 ◽  
pp. 073112142110351
Author(s):  
Rob Clark ◽  
Jeffrey Kentor
Keyword(s):  
Economic Growth ◽  
Social Network ◽  
Social Network Analysis ◽  
Network Analysis ◽  
Direct Investment ◽  
Fixed Effects ◽  
Foreign Capital ◽  
Global Network ◽  
Data Sets ◽  
The Impact

Foreign direct investment (FDI) holds a substantial and rapidly growing presence across every region of the world. However, our understanding of how foreign capital impacts economic growth in receiving and investing countries remains in question, despite nearly five decades of research. Our study contributes to this long-standing debate by (1) applying social network analysis to the FDI-growth literature, (2) utilizing recently available bilateral data for a global sample of countries during the post-2000 period, and (3) examining the impact of both inward and outward foreign capital on economic growth. While conventional measures of FDI typically focus on investment volume, we argue that the network structure of investment relations may be equally—or more—important. We construct a global network of FDI during the 2001–2017 period, bringing together two data sets: (1) the United Nations Conference on Trade and Development’s Bilateral FDI Statistics, and (2) the International Monetary Fund’s Coordinated Direct Investment Survey. We then calculate network centrality scores that reflect each country’s level of inward and outward embeddedness in the global FDI network. Drawing from a sample of 1,467 observations across 137 countries during the 2001–2017 period, we estimate two-way fixed effects models to examine the effect of FDI centrality on economic growth. Net of other predictors, we find that inward and outward centrality are positively—and independently—associated with growth, while more conventional measures of foreign capital display weaker and inconsistent effects.

scholarly journals Bridging global and local topology in whole-brain networks using the network statistic jackknife

2020 ◽  
Vol 4 (1) ◽  
pp. 70-88 ◽  
Author(s):  
Teague R. Henry ◽  
Kelly A. Duffy ◽  
Marc D. Rudolph ◽  
Mary Beth Nebel ◽  
Stewart H. Mostofsky ◽  
...  
Keyword(s):  
Network Analysis ◽  
Network Structure ◽  
R Package ◽  
Brain Network ◽  
Global Network ◽  
Local Network ◽  
Network Organization ◽  
Whole Brain ◽  
Global Efficiency ◽  
Global Topology

Whole-brain network analysis is commonly used to investigate the topology of the brain using a variety of neuroimaging modalities. This approach is notable for its applicability to a large number of domains, such as understanding how brain network organization relates to cognition and behavior and examining disrupted brain network organization in disease. A benefit to this approach is the ability to summarize overall brain network organization with a single metric (e.g., global efficiency). However, important local differences in network structure might exist without any corresponding observable differences in global topology, making a whole-brain analysis strategy unlikely to detect relevant local findings. Conversely, using local network metrics can identify local differences, but are not directly informative of differences in global topology. Here, we propose the network statistic (NS) jackknife framework, a simulated lesioning method that combines the utility of global network analysis strategies with the ability to detect relevant local differences in network structure. We evaluate the NS jackknife framework with a simulation study and an empirical example comparing global efficiency in children with attention-deficit/hyperactivity disorder (ADHD) and typically developing (TD) children. The NS jackknife framework has been implemented in a public, open-source R package, netjack, available at https://cran.r-project.org/package=netjack .

Bridging Global and Local Topology in Whole-brain Networks using the Network Statistic Jackknife

2018 ◽  
Author(s):  
Teague R Henry ◽  
Kelly A. Duffy ◽  
Marc D. Rudolph ◽  
Mary Beth Nebel ◽  
Stewart H. Mostofsky ◽  
...  
Keyword(s):  
Network Analysis ◽  
Network Structure ◽  
Developmental Trajectories ◽  
R Package ◽  
Brain Network ◽  
Global Network ◽  
Group Differences ◽  
Network Organization ◽  
Whole Brain ◽  
Global Efficiency

Whole-brain network analysis is commonly used to investigate the topology of the brain in a variety of neuroimaging modalities. This approach is notable for its applicability to a large number of domains, such as understanding how brain network organization relates to cognition and behavior, examining disrupted brain network organization in disease, and assessing developmental trajectories across the lifespan. A benefit to this approach is the ability to summarize overall brain network organization with a single number (e.g., global efficiency). However, important local differences in network structure might exist without any corresponding observable differences in overall topology, making a whole-brain analysis strategy unlikely to detect relevant local findings. Here, we propose the network-based statistic (NBS) jackknife as a means of combining the utility of global network analysis strategies with the ability to detect relevant local differences in network structure. We describe the NBS jackknife framework, and demonstrate three specific testing scenarios in a series of examples. Finally, we provide an empirical example comparing global efficiency between children with ADHD and typically developing (TD) children. We demonstrate using functional connectivity data that there are no group differences in whole-brain global efficiency. Using the NBS jackknife, however, we identify group differences in global efficiency specific to the salience and subcortical subnetworks. The NBS jackknife framework has been implemented in a public, open source R package, netjack, available at https://cran.r-project.org/package=netjack.

scholarly journals Reproducing scientists’ mobility: a data-driven model

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Giacomo Vaccario ◽  
Luca Verginer ◽  
Frank Schweitzer
Keyword(s):  
Decision Rules ◽  
Migration Policy ◽  
Large Data ◽  
Global Scale ◽  
Global Network ◽  
Data Sets ◽  
Mobility Patterns ◽  
Agent Based ◽  
Hiring Process ◽  
Geographical Distances

AbstractHigh skill labour is an important factor underpinning the competitive advantage of modern economies. Therefore, attracting and retaining scientists has become a major concern for migration policy. In this work, we study the migration of scientists on a global scale, by combining two large data sets covering the publications of 3.5 million scientists over 60 years. We analyse their geographical distances moved for a new affiliation and their age when moving, this way reconstructing their geographical “career paths”. These paths are used to derive the world network of scientists’ mobility between cities and to analyse its topological properties. We further develop and calibrate an agent-based model, such that it reproduces the empirical findings both at the level of scientists and of the global network. Our model takes into account that the academic hiring process is largely demand-driven and demonstrates that the probability of scientists to relocate decreases both with age and with distance. Our results allow interpreting the model assumptions as micro-based decision rules that can explain the observed mobility patterns of scientists.

scholarly journals Bayesian Network Structure and Predictability of Autistic Traits

2020 ◽  
pp. 003329412097815
Author(s):  
Giovanni Briganti ◽  
Donald R. Williams ◽  
Joris Mulder ◽  
Paul Linkowski
Keyword(s):  
Sex Differences ◽  
Network Analysis ◽  
Bayesian Network ◽  
Network Structure ◽  
Network Connectivity ◽  
Autistic Traits ◽  
Data Set ◽  
Conditional Dependence ◽  
Bayesian Network Structure ◽  
Male Subjects

The aim of this work is to explore the construct of autistic traits through the lens of network analysis with recently introduced Bayesian methods. A conditional dependence network structure was estimated from a data set composed of 649 university students that completed an autistic traits questionnaire. The connectedness of the network is also explored, as well as sex differences among female and male subjects in regard to network connectivity. The strongest connections in the network are found between items that measure similar autistic traits. Traits related to social skills are the most interconnected items in the network. Sex differences are found between female and male subjects. The Bayesian network analysis offers new insight on the connectivity of autistic traits as well as confirms several findings in the autism literature.

scholarly journals Tight knit under stress: colony resilience to the loss of tandem leaders during relocation in an Indian ant

2015 ◽  
Vol 2 (9) ◽  
pp. 150104 ◽  
Author(s):  
Swetashree Kolay ◽  
Sumana Annagiri
Keyword(s):  
Network Analysis ◽  
Social Insects ◽  
Network Structure ◽  
Similar Rate ◽  
Tandem Running ◽  
Frequent Event ◽  
Random Removal ◽  
Task Organization

The movement of colonies from one nest to another is a frequent event in the lives of many social insects and is important for their survival and propagation. This goal-oriented task is accomplished by means of tandem running in some ant species, such as Diacamma indicum . Tandem leaders are central to this process as they know the location of the new nest and lead colony members to it. Relocations involving targeted removal of leaders were compared with unmanipulated and random member removal relocations. Behavioural observations were integrated with network analysis to examine the differences in the pattern of task organization at the level of individuals and that of the colony. All colonies completed relocation successfully and leaders who substituted the removed tandem leaders conducted the task at a similar rate having redistributed the task in a less skewed manner. In terms of network structure, this resilience was due to significantly higher density and outcloseness indicating increased interaction between substitute leaders. By contrast, leader–follower interactions and random removal networks showed no discernible changes. Similar explorations of other goal-oriented tasks in other societies will possibly unveil new facets in the interplay between individuals that enable the group to respond effectively to stress.

The Location and Global Network Structure of Maritime Advanced Producer Services

Urban Studies ◽  
2011 ◽  
Vol 48 (13) ◽  
pp. 2749-2769 ◽  
Author(s):  
Wouter Jacobs ◽  
Hans Koster ◽  
Peter Hall
Keyword(s):  
Network Structure ◽  
Global Network ◽  
Producer Services ◽  
Advanced Producer Services

New Evidence on Eastern Europe's Pollution Progress

2003 ◽  
Vol 3 (1) ◽  
Author(s):  
Matthew E Kahn
Keyword(s):  
Sulfur Dioxide ◽  
Carbon Dioxide Emissions ◽  
National Level ◽  
Data Sets ◽  
Local Public Good ◽  
Data Set ◽  
The Czech Republic ◽  
Level Data ◽  
Good Improvement ◽  
New Evidence

Abstract Under communism, Eastern Europe's cities were significantly more polluted than their Western European counterparts. An unintended consequence of communism's decline is to improve urban environmental quality. This paper uses several new data sets to measure these gains. National level data are used to document the extent of convergence across nations in sulfur dioxide and carbon dioxide emissions. Based on a panel data set from the Czech Republic, Hungary and Poland, ambient sulfur dioxide levels have fallen both because of composition and technique effects. The incidence of this local public good improvement is analyzed.

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