Assortativity coefficient-based estimation of population patterns of sexual mixing when cluster size is informative.
OBJECTIVE
Population sexual mixing patterns can be quantified using Newman's assortativity coefficient (r). Suggested methods for estimating the SE for r may lead to inappropriate statistical conclusions in situations where intracluster correlation is ignored and/or when cluster size is predictive of the response. We describe a computer-intensive, but highly accessible, within-cluster resampling approach for providing a valid large-sample estimated SE for r and an associated 95% CI.


METHODS
We introduce needed statistical notation and describe the within-cluster resampling approach. Sexual network data and a simulation study were employed to compare within-cluster resampling with standard methods when cluster size is informative.


RESULTS
For the analysis of network data when cluster size is informative, the simulation study demonstrates that within-cluster resampling produces valid statistical inferences about Newman's assortativity coefficient, a popular statistic used to quantify the strength of mixing patterns. In contrast, commonly used methods are biased with attendant extremely poor CI coverage. Within-cluster resampling is recommended when cluster size is informative and/or when there is within-cluster response correlation.


CONCLUSIONS
Within-cluster resampling is recommended for providing valid statistical inferences when applying Newman's assortativity coefficient r to network data.
University of North Carolina, Chapel Hill, North Carolina, USA.
Siobhan K
SK
Young
Rollins School of Public Health, Emory University, Atlanta, Georgia, USA.
Robert H
RH
Lyles
University of North Carolina, Chapel Hill, North Carolina, USA.
Lawrence L
LL
Kupper
University of North Carolina, Chapel Hill, North Carolina, USA.
Jessica R
JR
Keys
University of North Carolina, Chapel Hill, North Carolina, USA.
Sandra L
SL
Martin
FHI 360, Durham, North Carolina, USA.
Elizabeth C
EC
Costenbader
D003198:Computer Simulation; D005260:Female; D015658:HIV Infections / Q000453:epidemiology* / Q000635:transmission; D006801:Humans; D008297:Male; D015233:Models, Statistical; D018401:Sample Size; D012725:Sexual Behavior / Q000706:statistics & numerical data*; D012749:Sexually Transmitted Diseases / Q000453:epidemiology; D013223:Statistics as Topic
Mathematical Model; Reproductive Health; Sexual Networks; Transmission Dynamics