Assortativity coefficient-based estimation of population patterns of sexual mixing when cluster size is informative.

OBJECTIVES: 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.

Perceived neighborhood safety and depressive symptoms among African American crack users.

This study examined the association between perceived neighborhood safety and depressive symptoms among 443 out-of-treatment African American crack cocaine users interviewed between 2000 and 2002 in North Carolina and tested the regression of depression on perceived neighborhood safety and common predictors of depression. Perceived neighborhood safety was an important predictor of depressive symptoms in models that adjusted for other correlates of depression. The findings are limited by the cross-sectional nature of the data and the complex etiology and course of depression. Additional research is needed to clarify the relationship between perceived neighborhood safety and depression. The study was supported by the National Institute on Drug Abuse.

Health care-based interventions for women who have experienced sexual violence: a review of the literature.

Thirty publications that evaluated health care-based interventions for women who experienced sexual violence were reviewed. The findings highlight that clinicians often need training in the provision sexual assault care, and that not all emergency departments have sexual assault care protocols. Studies examining effectiveness found that Sexual Assault Nurse Examiner programs are very helpful, that health care-based sexual assault treatment settings attract more women than do forensic-based settings, that sexual assault survivors often prefer a combination of medication and counseling treatment, and that preexam administration of a video explaining the collection of forensic evidence may reduce women's stress during the procedure. Studies on postexposure HIV prophylaxis found that many women did not complete the treatment regimen, often because of side effects. Emergency contraception to prevent postrape pregnancy is not consistently offered to women. Only one study reported on abortion as part of the range of sexual assault services.