1. Surrogacy assessment using principal stratification with multivariate normal and Gaussian copula models.

    Clinical Trials 12(4):317 (2015) PMID 25490988

    The validation of intermediate markers as surrogate markers (S) for the true outcome of interest (T) in clinical trials offers the possibility for trials to be run more quickly and cheaply by using the surrogate endpoint in place of the true endpoint. Working within a principal stratification fr...
  2. Young driver crash rates by licensing age, driving experience, and license phase.

    Accident Analysis & Prevention 80:243 (2015) PMID 25939133

    Few studies have concurrently assessed the influence of age and experience on young driver crashes, in particular in the post-Graduated Driver Licensing (GDL) era. Further, little attention is given to the transition from intermediate to full licensure. We examined the independent and joint cont...
  3. Discussion of "On Bayesian Estimation of Marginal Structural Models".

    Biometrics 71(2):288 (2015) PMID 25773004

  4. Joint modeling of cross-sectional health outcomes and longitudinal predictors via mixtures of means and variances.

    Biometrics 71(2):487 (2015) PMID 25652674 PMCID PMC4480207

    Joint modeling methods have become popular tools to link important features extracted from longitudinal data to a primary event. While most modeling strategies have focused on the association between the longitudinal mean trajectories and risk of an event, we consider joint models that incorpora...
  5. Dynamics of health behaviours and socioeconomic differences in mortality in the USA.

    Journal of Epidemiology & Community Health 69(5):416 (2015) PMID 25563741 PMCID PMC4451600

    To measure the explanatory role of behavioural factors to educational and income disparities in mortality among US adults (ages 25+). Data were from four waves of the American Changing Lives Study (N=3617). There were 1832 deaths between 1986 and 2011. Smoking, physical activity, alcohol and bod...
  6. Surrogacy marker paradox measures in meta-analytic settings.

    Biostatistics 16(2):400 (2015) PMID 25236906

    Because of the time and expense required to obtain clinical outcomes of interest, such as functional limitations or death, clinical trials often focus the effects of treatment on earlier and more easily obtained surrogate markers. Preliminary work to define surrogates focused on the fraction of ...
  7. Surrogacy marker paradox measures in meta-analytic settings.

    Biostatistics 16(2):400 (2015) PMID 25236906 PMCID PMC4366594

    Because of the time and expense required to obtain clinical outcomes of interest, such as functional limitations or death, clinical trials often focus the effects of treatment on earlier and more easily obtained surrogate markers. Preliminary work to define surrogates focused on the fraction of ...
  8. Young driver licensing: Examination of population-level rates using New Jersey's state licensing database.

    Accident Analysis & Prevention 76:49 (2015) PMID 25590921

    Recent surveys have provided insight on the primary reasons why US teens delay licensure but are limited in their ability to estimate licensing rates and trends. State administrative licensing data are the ideal source to provide this information but have not yet been analyzed for this purpose. ...
  9. Influence of race/ethnicity, body mass index, and proximity of menopause on menstrual cycle patterns in the menopausal transition: the Study of Women's Health Across the Nation.

    Menopause 22(2):159 (2015) PMID 25026113

    Few studies have evaluated factors that influence menstrual cycle length (MCL) during the menopausal transition (MT), a life stage during which very long cycles become more likely to occur. The objective of this article was to assess how body mass index and race/ethnicity-factors associated with...
  10. Influence of race/ethnicity, body mass index, and proximity of menopause on menstrual cycle patterns in the menopausal transition: the Study of Women's Health Across the Nation.

    Menopause 22(2):159 (2015) PMID 25026113 PMCID PMC4295005

    Few studies have evaluated factors that influence menstrual cycle length (MCL) during the menopausal transition (MT), a life stage during which very long cycles become more likely to occur. The objective of this article was to assess how body mass index and race/ethnicity-factors associated with...
  11. Long-term changes in crash rates after introduction of a graduated driver licensing decal provision.

    American Journal of Preventive Medicine 48(2):121 (2015) PMID 25376478

    New Jersey (NJ) implemented the first Graduated Driver Licensing (GDL) decal provision in the U.S. in May 2010. An initial study reported a 1-year post-decal decrease in the crash rate among NJ intermediate drivers aged <21 years. Longer-term analysis is critical for policymakers in other states...
  12. Influence of race/ethnicity, body mass index, and proximity of menopause on menstrual cycle patterns in the menopausal transition: the Study of Women's Health Across the Nation.

    Menopause 22(2):159 (2015) PMID 25026113 PMCID PMC4295005

    Few studies have evaluated factors that influence menstrual cycle length (MCL) during the menopausal transition (MT), a life stage during which very long cycles become more likely to occur. The objective of this article was to assess how body mass index and race/ethnicity-factors associated with...
  13. Influence of race/ethnicity, body mass index, and proximity of menopause on menstrual cycle patterns in the menopausal transition: the Study of Women's Health Across the Nation.

    Menopause 22(2):159 (2015) PMID 25026113 PMCID PMC4295005

    Few studies have evaluated factors that influence menstrual cycle length (MCL) during the menopausal transition (MT), a life stage during which very long cycles become more likely to occur. The objective of this article was to assess how body mass index and race/ethnicity-factors associated with...
  14. Long-term changes in crash rates after introduction of a Graduated Driver Licensing decal provision.

    American Journal of Preventive Medicine 48(2):121 (2015) PMID 25376478

    New Jersey (NJ) implemented the first Graduated Driver Licensing (GDL) decal provision in the U.S. in May 2010. An initial study reported a 1-year post-decal decrease in the crash rate among NJ intermediate drivers aged <21 years. Longer-term analysis is critical for policymakers in other states...
  15. Engagement with the TeenDrivingPlan and diversity of teens' supervised practice driving: lessons for internet-based learner driver interventions.

    Injury Prevention 21(1):4 (2015) PMID 24916684

    Inexperienced, less-skilled driving characterises many newly licensed drivers and contributes to high crash rates. A randomised trial of TeenDrivingPlan (TDP), a new learner driver phase internet-based intervention, demonstrated effectiveness in improving safety relevant, on-road driving behavio...
  16. Engagement with the TeenDrivingPlan and diversity of teens' supervised practice driving: lessons for internet-based learner driver interventions.

    Injury Prevention 21(1):4 (2015) PMID 24916684

    Inexperienced, less-skilled driving characterises many newly licensed drivers and contributes to high crash rates. A randomised trial of TeenDrivingPlan (TDP), a new learner driver phase internet-based intervention, demonstrated effectiveness in improving safety relevant, on-road driving behavio...
  17. Joint modeling compliance and outcome for causal analysis in longitudinal studies.

    Statistics in Medicine 33(20):3453 (2014) PMID 23576159 PMCID PMC3788835

    This article discusses joint modeling of compliance and outcome for longitudinal studies when noncompliance is present. We focus on two-arm randomized longitudinal studies in which subjects are randomized at baseline, treatment is applied repeatedly over time, and compliance behaviors and clinic...
  18. Joint modeling compliance and outcome for causal analysis in longitudinal studies.

    Statistics in Medicine 33(20):3453 (2014) PMID 23576159 PMCID PMC3788835

    This article discusses joint modeling of compliance and outcome for longitudinal studies when noncompliance is present. We focus on two-arm randomized longitudinal studies in which subjects are randomized at baseline, treatment is applied repeatedly over time, and compliance behaviors and clinic...
  19. Effect of the teen driving plan on the driving performance of teenagers before licensure: a randomized clinical trial.

    JAMA Pediatrics 168(8):764 (2014) PMID 24957844

    Many studies have failed to show an effect of parent-supervised practice driving on the driving performance of teenagers; nevertheless, most Graduated Driver Licensing programs have provisions that require supervised practice. To determine whether a web-based intervention, the Teen Driving Plan ...
  20. Effect of the teen driving plan on the driving performance of teenagers before licensure: a randomized clinical trial.

    JAMA Pediatrics 168(8):764 (2014) PMID 24957844

    Many studies have failed to show an effect of parent-supervised practice driving on the driving performance of teenagers; nevertheless, most Graduated Driver Licensing programs have provisions that require supervised practice. To determine whether a web-based intervention, the Teen Driving Plan ...