Shu Xu

Shu (Violet) Xu
Shu Xu

Clinical Assistant Professor of Biostatistics

Professional overview

Dr. Shu Xu’s work represents a balance of both statistical and applied aspects of quantitative methodology. Her primary quantitative interests include evaluating and developing statistical methods for longitudinal data analysis. Specifically, Dr. Xu’s research focuses on various aspects of latent growth models, missing data methods, and causal inference models.

Dr. Xu has collaborated with substance use, family, and health researchers to advance and share her knowledge of quantitative methodology and pursue a better understanding of the social sciences and public health. She has conducted research with the Family Translational Research Group at NYU and the Methodology Center at the Pennsylvania State University.

Education

BS, Psychology, East China Normal University, Shanghai, China
MS, Quantitative Psychology, University of California, Davis
PhD, Quantitative Psychology, University of California, Davis

Areas of research and study

Biostatistics
Family research
Longitudinal Data Analysis
Missing Data Methods
Mixture Models
Quantitative Research

Publications

Publications

Use of electronic nicotine delivery system (ENDS) devices among U.S. Youth and adults: Findings from the Population Assessment of Tobacco and Health Study Waves 1–5

Jiang, N., Xu, S., Li, L., Cleland, C. M., & Niaura, R. S. (n.d.).

Publication year

2023

Journal title

Addictive Behaviors

Volume

139
Abstract
Abstract
Introduction: Electronic nicotine delivery system (ENDS) devices evolve rapidly and impact nicotine dependence. This study described the type of ENDS devices used most frequently by U.S. youth and adults from 2013/14 to 2018/19. Methods: We analyzed Waves 1–5 data of the Population Assessment of Tobacco and Health Study. Among current ENDS users, descriptive statistics summarized the most frequently used ENDS devices (i.e., disposable cigalike, refillable cartridge, nonrefillable cartridge, tank, mod, prefilled pod, disposable pod) among youth (12–17 years), young adults (18–34 years), and older adults (≥35 years) for each wave. Results: The proportion of current ENDS users who reported they most frequently used disposable cigalikes and cartridge-based devices declined over time across all age groups. At Waves 1–4, tank was generally the most popular type for all ages and an increasing proportion of ENDS users reported they most frequently used tanks. The primary use of mods decreased among youth, and fluctuated among young and older adults. At Wave 5, prefilled pods became the dominant type (youth: 55.0%; young adults: 44.7%; older adults: 42.7%), and 4.2–10.0% of ENDS users reported using disposable pods most often. The popularity of tanks, mods, and prefilled pods was more evident in youth and young adults, and primary use of disposable pods was more common in older adults. Conclusions: The primary use of ENDS devices changed over the years and varied by age. More research is warranted to continuously monitor the characteristics of ENDS devices in youth and adults to inform product regulations and intervention efforts.

Cigar Use Progression Among New Cigar Initiators: A Two-Part Growth Curve Analysis Among a Youth and Young Adult Cohort

Cantrell, J., Xu, S., Kreslake, J., Liu, M., & Hair, E. (n.d.).

Publication year

2022

Journal title

Nicotine and Tobacco Research

Volume

24

Issue

1

Page(s)

28-36
Abstract
Abstract
Introduction: Youth and young adults (YYAs) are at high risk of cigar use. This study's objective was to examine progression and sociodemographic differences in current cigar use and frequency among new cigar initiators. Aims and Methods: We conducted a two-part latent growth model among a nationally representative cohort of cigar initiators (aged 15-25) to examine 24-month trajectories of current cigar use and frequency (n = 1483). The cohort was recruited via address-based sampling with online data collection from 2014 to 2019 and surveyed approximately every 6 months. Results: The unconditional odds of current cigar use (ie, past 30-day use) within 6 months of initiation was 0.72 (95% confidence interval: 0.63, 0.82), corresponding to a probability of 42%. The odds of current use among recent cigar initiates declined 6 months after initiation and was followed by a stabilization in use over time. Among continued users, frequency (# days used in past 30 days) increased linearly over time but remained low (3.47 days/months at 24 months). Younger individuals, non-Hispanic African Americans, those with lower subjective financial status, and current users of cigarettes, other tobacco products and/or marijuana were at highest risk within 6 months of initiation. Males, younger users, and current cigarette smokers had the highest risk for cigar progression over time. Conclusions: This study is the first to examine longitudinal cigar use patterns among YYA cigar initiators. Findings emphasize the need for research across the cigar use spectrum and the importance of interventions targeted by age, stage of use, cigarette, other tobacco, and marijuana use and key sociodemographics to interrupt use pathways. Implications: This study is the first to examine progression of cigar use among YYAs who have newly initiated cigars. Results show a high probability of current cigar use within 6 months of initiation followed by a rapid decline and stabilization over time. Frequency increases among those who continue using cigars. Males, younger users, and current cigarette smokers had the highest risk for cigar progression over time. Findings emphasize the need for targeting interventions by age, stage of use, cigarette, other tobacco, and marijuana use and key sociodemographics to interrupt use pathways.

Passive exposure to e-cigarette emissions is associated with worsened mental health

Farrell, K. R., Weitzman, M., Karey, E., Lai, T. K., Gordon, T., & Xu, S. (n.d.).

Publication year

2022

Journal title

BMC public health

Volume

22

Issue

1
Abstract
Abstract
Background: Cigarette smoking, secondhand cigarette smoke (SHS) exposure, and e-cigarette use (“vaping”) are each associated with increased rates of depressive symptoms and other internalizing mental health disorders. The prevalence of vaping has increased greatly, yet the mental health correlates of secondhand exposure to e-cigarette emissions are as yet to be investigated. This study examined the potential adverse mental health outcomes associated with different tobacco exposures (direct and passive), with a particular focus on the mental health correlates of secondhand exposure to e-cigarette emissions. Methods: The Population Assessment of Tobacco and Health Study data collected from a sample of 16,173 Wave 4 adults were used to test the hypothesis that secondhand e-cigarette emissions exposure is associated with increased odds of internalizing mental health disorders. Individuals were categorized as exclusive cigarette smokers, exclusive e-cigarette users, cigarette and e-cigarette dual users, exclusive noncombustible tobacco users, secondhand smoke exposed non-users, secondhand e-cigarette emissions exposed non-users, and non-users with no current SHS/secondhand e-cigarette aerosol exposure. Adjusted weighted logistic regression analysis was used to investigate the association between exposure type and internalizing problems as assessed by scores on the Global Appraisal of Individual Needs-Short Screener (GAIN-SS), a widely used instrument for assessing mental health problems. Results: Cigarette smokers (AOR = 2.53, 95% CI: 2.19–2.92), e-cigarette users (AOR = 3.14, 2.41–4.09), dual users (AOR = 3.37, 2.85–4.00), noncombustible tobacco users (AOR = 1.48, 1.01–2.17), SHS exposed non-users (AOR = 1.63, 1.37–1.94), and secondhand e-cigarette emissions exposed non-users (AOR = 1.43, 1.03–1.99) were each associated with increased odds of moderate to severe internalizing mental health problems as compared to unexposed non-users. Odds of internalizing problems among SHS and secondhand e-cigarette emissions exposed non-users did not differ (p = 0.46). Conclusions: This is the first study, to our knowledge, to identify an association between recent secondhand exposure to e-cigarette emissions and mental health problems, and the risk is comparable to that of SHS. Corroboration of this relationship needs further research to explicate directionality and mechanisms underlying this association.

Recurrent Injecting Drug Use as a Mediator between Psychiatric Disorder and Non-Fatal Overdose

Barnes, D., Xu, V. S., Cleland, C. M., McKnight, C., & Des Jarlais, D. (n.d.).

Publication year

2022

Journal title

Substance Use and Misuse

Volume

57

Issue

8

Page(s)

1248-1256
Abstract
Abstract
Background: Unintentional drug overdose has increased markedly in the United States. Studies document an association between psychiatric disorder and unintentional overdose; we extend this research through a preliminary test of a causal model of recurrent injection drug use mediating this relationship. Methods: In a cross-sectional study of 241 adults in New York City with a possible current substance use disorder, we conducted conventional and Imai’s mediation analyses to examine if psychiatric disorder is associated with increased prevalence of ever overdosing and if recurrent injection drug use mediates this association. Our cross-sectional data permit the first step of assessing causal models: testing if statistical associations are consistent with the model. Results: Fifty-eight percent of the sample endorsed previous psychiatric disorder diagnosis and 35.7% reported ever overdosing. Imai’s mediation analysis showed that, adjusting for covariates, the total association between psychiatric diagnosis and ever overdosing (adjusted prevalence difference [aPD] = 0.16, 95% CI 0.04–0.28) was composed of a direct effect (aPD = 0.09, 95% CI −0.03 − 0.21, p = 0.136) and an indirect effect (aPD = 0.07, 95% CI 0.02–0.13). Recurrent injecting drug use contributed to 42% (ratio of indirect effect to total effect; 95% CI 12 − 100%, p = 0.02) of the association between psychiatric diagnosis and ever overdosing. Conventional mediation analysis produced similar results. Conclusions: Our results provide a warrant for taking the necessary next step for assessing a causal model using longitudinal data, potentially providing a strong rationale for intervening on psychiatric disorders to stem overdose.

Relationships Between E-cigarette Use and Subsequent Cigarette Initiation Among Adolescents in the PATH Study: an Entropy Balancing Propensity Score Analysis

Xu, S., Coffman, D. L., Liu, B., Xu, Y., He, J., & Niaura, R. S. (n.d.).

Publication year

2022

Journal title

Prevention Science

Volume

23

Issue

4

Page(s)

608-617
Abstract
Abstract
This study aimed to examine the relationship between electronic cigarette use and subsequent combustible cigarette use, controlling for confounding by using a propensity score method approach. Data from the first three annual waves of the Population Assessment of Tobacco and Health study were analyzed (n = 6309). Participants were tobacco-naïve at Wave 1; used e-cigarettes exclusively (n = 414), used combustible cigarettes exclusively (n = 46), or not used any tobacco products (n = 5849) at Wave 2. We conducted entropy balancing propensity score analysis to examine the association between exclusive e-cigarette or cigarette initiation and subsequent cigarette use at Wave 3, adjusting for non-response bias, sampling bias, and confounding. Among tobacco-naïve youth, exclusive e-cigarette use was associated with greater risk for subsequent combustible cigarette smoking initiation (OR = 3.42, 95% CI = (1.99, 5.93)) and past 30-day combustible cigarette use (OR = 2.88, 95% CI = (1.22, 6.86)) in the following year. However, the latter risk was comparatively lower than the risk if youth started with a combustible cigarette (OR = 25.79, 95% CI = (9.68, 68.72)). Results of sensitivity analyses indicated that estimated effects were robust to unmeasured confounding. Use of e-cigarettes in tobacco-naïve youth is associated with increased risk of subsequent past 30-day combustible cigarette use but the risk is an order of magnitude higher if they start with a combustible cigarette.

The Mediating Effect of E-Cigarette Harm Perception in the Relationship between E-Cigarette Advertising Exposure and E-Cigarette Use

Jiang, N., Xu, S., Li, L., El-Shahawy, O., Freudenberg, N., Shearston, J. A., & Sherman, S. E. (n.d.).

Publication year

2022

Journal title

International journal of environmental research and public health

Volume

19

Issue

10
Abstract
Abstract
Exposure to e-cigarette advertising is associated with e-cigarette use among young people. This study examined the mediating effect of e-cigarette harm perception on the above relationship. Cross-sectional survey data were collected from 2112 college students in New York City in 2017–2018. The analytic sample comprised 2078 participants (58.6% females) who provided completed data. Structural equal modeling was performed to examine if e-cigarette harm perception mediated the relationship between e-cigarette advertising exposure (via TV, radio, large signs, print media, and online) and ever e-cigarette use and susceptibility to e-cigarette use. About 17.1% of participants reported ever e-cigarette use. Of never users, 17.5% were susceptible to e-cigarette use. E-cigarette advertising exposure was mainly through online sources (31.5%). Most participants (59.4%) perceived e-cigarettes as equally or more harmful than cigarettes. Advertising exposure showed different effects on e-cigarette harm perception depending on the source of the advertising exposure, but perceiving e-cigarettes as less harmful than cigarettes was consistently associated with e-cigarette use and susceptibility. Low harm perception mediated the association between advertising exposure (via online, TV, and radio) and ever e-cigarette use and between online advertising exposure and e-cigarette use susceptibility. Regulatory actions are needed to address e-cigarette marketing, particularly on the Internet.

Youth E-Cigarette Use and Functionally Important Respiratory Symptoms: The Population Assessment of Tobacco and Health (PATH) Study Waves 3 and 4

Stevens, E. R., Xu, S., Niaura, R., Cleland, C. M., Sherman, S. E., Mai, A., Karey, E., & Jiang, N. (n.d.).

Publication year

2022

Journal title

International journal of environmental research and public health

Volume

19

Issue

22
Abstract
Abstract
Respiratory effects of e-cigarette use among youth are not fully understood. This study investigated the longitudinal association between e-cigarette use and a validated index of functionally important respiratory symptoms among US youth. Data from Waves 3–4 of the Population Assessment of Tobacco and Health Study were analyzed. The sample included youth (aged 12–17) without asthma at baseline (Wave 3), who completed a follow-up survey (Wave 4), and were not missing data for analytic variables (n = 3899). Exposure was e-cigarette use status (never, former, or current) at baseline. The outcome was a respiratory symptom index based on responses for seven wheezing items at Wave 4. An index of ≥2 was defined as having functionally important respiratory symptoms. Lagged logistic regression models examined the association between baseline e-cigarette use and functionally important respiratory symptoms at follow-up by combustible tobacco use status (never or ever), and controlling for baseline covariates. At baseline, 13.7% of participants reported former e-cigarette use, and 4.3% reported current use. Baseline e-cigarette use did not increase the odds of having functionally important respiratory symptoms at follow-up regardless of combustible tobacco use status. Future research on larger populations of e-cigarette users with longer follow-up periods will improve our understanding of the respiratory risks associated with e-cigarette use among youth.

Cannabis Use and the Onset of Cigarette and E-cigarette Use: A Prospective, Longitudinal Study among Youth in the United States

Weinberger, A. H., Zhu, J., Lee, J., Xu, S., & Goodwin, R. D. (n.d.).

Publication year

2021

Journal title

Nicotine and Tobacco Research

Volume

23

Issue

3

Page(s)

609-613
Abstract
Abstract
Introduction: Cigarette use is declining among youth in the United States, whereas cannabis use and e-cigarette use are increasing. Cannabis use has been linked with increased uptake and persistence of cigarette smoking among adults. The goal of this study was to examine whether cannabis use is associated with the prevalence and incidence of cigarette, e-cigarette, and dual product use among U.S. youth. Methods: Data included U.S. youth ages 12-17 from two waves of the Population Assessment of Tobacco and Health (PATH) Study (Wave 1 youth, n = 13 651; Wave 1 tobacco-naive youth, n = 10 081). Weighted logistic regression models were used to examine the association between Wave 1 cannabis use and (1) Wave 1 prevalence of cigarette/e-cigarette use among Wave 1 youth and (2) Wave 2 incidence of cigarette/e-cigarette use among Wave 1 tobacco-naive youth. Analyses were run unadjusted and adjusted for demographics and internalizing/externalizing problem symptoms. Results: Wave 1 cigarette and e-cigarette use were significantly more common among youth who used versus did not use cannabis. Among Wave 1 tobacco-naive youth, Wave 1 cannabis use was associated with significantly increased incidence of cigarette and e-cigarette use by Wave 2. Conclusions: Youth who use cannabis are more likely to report cigarette and e-cigarette use, and cannabis use is associated with increased risk of initiation of cigarette and e-cigarette use over 1 year. Continued success in tobacco control-specifically toward reducing smoking among adolescents-may require focusing on cannabis, e-cigarette, and cigarette use in public health education, outreach, and intervention efforts. Implications: These data extend our knowledge of cigarette and e-cigarette use among youth by showing that cannabis use is associated with increased prevalence and incidence of cigarette and e-cigarette use among youth, relative to youth who do not use cannabis. The increasing popularity of cannabis use among youth and diminished perceptions of risk, coupled with the strong link between cannabis use and tobacco use, may have unintended consequences for cigarette control efforts among youth.

E-cigarette use, systemic inflammation, and depression

Farrell, K. R., Karey, E., Xu, S., Gibbon, G., Gordon, T., & Weitzman, M. (n.d.).

Publication year

2021

Journal title

International journal of environmental research and public health

Volume

18

Issue

19
Abstract
Abstract
Background: E-cigarette use (vaping) is an emerging public health problem. Depression has been found to be associated with e-cigarette use, and vaping and depression are each associated with elevated systemic inflammation. To date, the role of inflammation in the relationship between vaping and depression has not been explored. Objective: To assess the independent associations between e-cigarette use, depression, and inflammation, and to investigate whether the likelihood of depression among current e-cigarette users is associated with systemic inflammation. Methods: Nationally representative NHANES data from 2015–2018 were used (n = 4961). Systemic inflammation was defined as serum C-reactive protein (CRP) ≥ 8.0 mg/L. Depressed individuals were characterized by a score ≥ 10 on the Patient Health Questionnaire-9 (PHQ-9). Current e-cigarette users were defined as individuals who vaped at least once in the past 30 days and these individuals were stratified by use: exclusive users (reported smoking less than 100 combustible cigarettes in their lifetime), dual users (reported current use of electronic and combustible cigarettes), and e-cigarette users who were previous smokers. Bivariate analyses were used to assess independent associations between vaping, depression, and inflammation; and weighted logistic regression analyses adjusting for BMI, sex, and economic status were used to determine the odds ratios (ORs) for depression by e-cigarette category stratified by differential CRP levels. Results: Depression occurred in 16.7% of all e-cigarette users vs. 5.0% of those who never used e-cigarettes (p < 0.001). In adjusted analyses, the following elevated ORs were found: all current e-cigarette users with CRP <8 = 3.37 (95% CI: 2.06, 5.51) vs. CRP ≥8 = 6.70 (2.48, 18.11); exclusive e-cigarette users with CRP <8 = 1.91 (0.78, 4.69) vs. those with CRP ≥8 = 5.09 (1.44, 18.02); and dual users with CRP <8 = 4.31 (2.35, 7.89) vs. those with CRP ≥8 = 7.37 (1.85, 29.41). These ORs indicate that depression is associated with each category of e-cigarette use; however, we found this association did not vary by systemic inflammation level (interaction p-values > 0.05). Conclusion: While a pattern of greater ORs for depression among e-cigarette users with elevated CRP provides provocative findings that might suggest a potential role of inflammation in the association between vaping and depression, we failed to find evidence that inflammation clearly moderates this association. While it is possible that depression among e-cigarette users may be influenced by systemic inflammation, a reproduction of the current study is necessary among a larger cohort to elucidate the effect of inflammation on depression among e-cigarette users.

Self-report measures of coercive process in couple and parent–child dyads.

Mitnick, D. M., Lorber, M. F., Smith Slep, A. M., Heyman, R. E., Xu, S., Bulling, L. J., Nichols, S. R., & Eddy, J. M. (n.d.).

Publication year

2021

Journal title

Journal of Family Psychology

Volume

35

Issue

3

Page(s)

388-398
Abstract
Abstract
One of the most influential behavioral models of family conflict is G. R. Patterson’s (1982) coercive family process theory. Self-reports for behaviors related to coercion (e.g., hostility toward a family member) abound; however, there are no self-report measures for coercive process itself, which is, by definition, a dyadic process. Operationalizations of coercive process are measured with behavioral observation, typically including sequential analyzed, microcoded behaviors. Despite its objectivity and rigor, coding of behavior observation is not always feasible in research and applied settings because of the high training, personnel, and time costs the observation requires. Because coercive process has been shown to predict a host of maladaptive outcomes (e.g., parent–child conflict, aggression, negative health outcomes) and given the complete absence of self-report measures of coercive process, we recently designed brief questionnaires to assess coercive process in couple (Couple Coercive Process Scale [CCPS]) and parent–child interactions (Parent–Child Coercive Process Scale [PCCPS]) and tested them via Qualtrics participant panels in samples recruited to mirror socioeconomic generalizability to U.S. Census data. The CCPS and PCCPS exhibited initial evidence of psychometric quality in measuring coercive process in couple and parent–child dyads: Both measures are unifactorial; have evidence of reliability, especially at higher levels of coercive process; and demonstrate concurrent validity with constructs in their nomological networks, with medium to large effect sizes.

High Sensitivity and Specificity Screening for Clinically Significant Intimate Partner Violence

Heyman, R. E., Baucom, K. J., Xu, S., Smith Slep, A. M., Snarr, J. D., Foran, H. M., Lorber, M. F., Wojda, A. K., & Linkh, D. J. (n.d.).

Publication year

2020

Journal title

Journal of Family Psychology
Abstract
Abstract
The U.S. Preventive Services Task Force has recommended that clinicians screen patients for intimate partner violence (IPV). This article aims to develop and test the first screeners for clinically significant physical and psychological IPV (i.e., acts meeting criteria in the International Classification of Diseases (11th ed.; ICD-11; World Health Organization, 2019) and the Diagnostic and Statistical Manual of Mental Disorders (5th ed.; DSM-5; American Psychiatric Association, 2013). The goal was to derive screeners that (1) are maximally brief, while still achieving high sensitivity and specificity; (2) assess perpetration and victimization when either men or women are reporting; and (3) use ICD-11/DSM-5 criteria as the reference standard. Random samples of active duty service members at 82 installations worldwide were obtained via e-mail invitation (2006: N = 54,543; 2008: N = 48,909); their response rates were excellent for long general population surveys with no payment (2006: 44.7%, 2008: 49.0%). The population of spouses at the participating installation was invited by mailed postcard (2006: N = 19,722; 2008: N = 12,127; response rates-2006: 12.3%, 2008: 10.8%). Clinically significant physical intimate partner violence can be effectively screened with as few as four items, with sensitivities >90% and specificities >95%; clinically significant psychological intimate partner violence can be screened with two items. Men and women can be screened with equivalent accuracy, as can those committing the violence and those victimized by it.

Psychology of wearing face masks to prevent transition of COVID-19

Song, L. J., Xu, S., Xu, S. L., Sun, Z., & Liu, W. (n.d.).

Publication year

2020

Journal title

General Psychiatry

Volume

33

Issue

6

The lump-versus-split dilemma in couple observational coding: A multisite analysis of rapid marital interaction coding system data.

Heyman, R. E., Otto, A. K., Reblin, M., Wojda, A. K., & Xu, S. (n.d.).

Publication year

2020

Journal title

Journal of Family Psychology

Volume

35

Issue

4
Abstract
Abstract
Historically, observational couple communication researchers have oscillated between splitting behaviors into narrowly defined discrete codes and grouping behaviors into broader codes—sometimes within the same study. We label this the “lump-versus-split dilemma.” Coding across a decade and 11 investigators were used to recommend the most meaningful number of codes to use when observing couples’ conflict. We combined data from 14 studies that used the Rapid Marital Interaction Coding System (RMICS) to score communication behavior during different-sex couples’ conflict interactions. In each study, couples completed at least one 10-min, video-recorded conflict discussion. Communication during these interactions was coded by trained research staff using RMICS; all codes were compiled into a single data set for descriptive analysis and exploratory factor analyses (EFAs). The final sample comprised N = 2,011 couples. Several RMICS codes were extremely infrequent—specifically, distress-maintaining attributions, psychological abuse, withdrawal, dysphoric affect, and relationship-enhancing attributions. By far, the most frequent code was constructive problem discussion. EFAs yielded two factors for both women and men. Factor 1 (Negative) contained two items: distress-maintaining attributions and hostility. Factor 2 (Nonnegative) contained constructive problem discussion and humor (and, for women only, acceptance). Results side heavily with the “lump” camp in the lump-versus-split dilemma in couple observational coding. These RMICS factor analysis results converge with those from other systems and imply that the microanalytic “splitting” era in couples coding should draw to a close, with future studies instead focused on negative, neutral, and positive codes. (PsycInfo Database Record (c) 2020 APA, all rights reserved)

Using Security Questions to Link Participants in Longitudinal Data Collection

Xu, S., Chan, A., Lorber, M. F., & Chase, J. P. (n.d.).

Publication year

2020

Journal title

Prevention Science

Volume

21

Issue

2

Page(s)

194-202
Abstract
Abstract
Anonymous data collection systems are often necessary when assessing sensitive behaviors but can pose challenges to researchers seeking to link participants over time. To assist researchers in anonymously linking participants, we outlined and tested a novel security question linking (security question linking; SEEK) method. The SEEK method includes four steps: (1) data management and standardization, (2) many-to-many matching, (3) fuzzy matching, and (4) rematching and verification. The method is demonstrated in SAS with two samples from a longitudinal study of adolescent dating violence. After an initial assessment during a laboratory visit, participants were asked to complete an online assessment either (a) once, 3 months later (Sample 1, n = 60), or (b) three times at 1-month intervals (Sample 2, n = 140). Demographics, eye color, and responses to nine security questions were used as key variables to link responses from the laboratory and online follow-up assessments. The rates of matched cases were 100% in Sample 1 and from 94.3 to 98.3% in Sample 2. To quantify the confidence in the data quality of successfully matched pairs, we reported the means and standard deviations of the number of matched security questions. In addition, we reported the rank order and counts of the mismatched components in key variables. Results indicate that the SEEK method provides a feasible and reliable solution to link responses in longitudinal studies with sensitive questions.

A Randomized, Controlled Trial of the Impact of the Couple CARE for Parents of Newborns Program on the Prevention of Intimate Partner Violence and Relationship Problems

Heyman, R. E., Slep, A. M., Lorber, M. F., Mitnick, D. M., Xu, S., Baucom, K. J., Halford, W. K., & Niolon, P. H. (n.d.).

Publication year

2019

Journal title

Prevention Science

Volume

20

Issue

5

Page(s)

620-631
Abstract
Abstract
Effective, accessible prevention programs are needed for adults at heightened risk for intimate partner violence (IPV). This parallel group randomized controlled trial examines whether such couples receiving the American version of Couple CARE for Parents of Newborns (CCP; Halford et al. 2009) following the birth of a child, compared with controls, report fewer first occurrences of clinically significant IPV, less frequent physical and psychological IPV, and improved relationship functioning. Further, we test whether intervention effects are moderated by level of risk for IPV. Couples at elevated risk for IPV (N = 368) recruited from maternity units were randomized to CCP (n = 188) or a 24-month waitlist (n = 180) and completed measures of IPV and relationship functioning at baseline, post-program (when child was 8 months old), and two follow-ups (at 15 and 24 months). Intervention effects were tested using intent to treat (ITT) as well as complier average causal effect (CACE; Jo and Muthén 2001) structural equation models. CCP did not significantly prevent clinically significant IPV nor were there significant main effects of CCP on clinically significant IPV, frequency of IPV, or most relationship outcomes in the CACE or ITT analyses. Risk moderated the effect of CCP on male-to-female physical IPV at post-program, with couples with a planned pregnancy declining, but those with unplanned pregnancies increasing. This study adds to previous findings that prevention programs for at-risk couples are not often effective and may even be iatrogenic for some couples.

Patterns of psychological health problems and family maltreatment among United States Air Force members

Lorber, M. F., Xu, S., Heyman, R. E., Slep, A. M., & Beauchaine, T. P. (n.d.).

Publication year

2018

Journal title

Journal of Clinical Psychology

Volume

74

Issue

7

Page(s)

1258-1271
Abstract
Abstract
Objectives:: We sought to identify subgroups of individuals based on patterns of psychological health problems (PH; e.g., depressive symptoms, hazardous drinking) and family maltreatment (FM; e.g., child and partner abuse). Method:: We analyzed data from very large surveys of United States Air Force active duty members with romantic partners and children. Results:: Latent class analyses indicated six replicable patterns of PH problems and FM. Five of these classes, representing ∼98% of survey participants, were arrayed ordinally, with increasing risk of multiple PH problems and FM. A sixth group defied this ordinal pattern, with pronounced rates of FM and externalizing PH problems, but without correspondingly high rates/levels of internalizing PH problems. Conclusions:: Ramifications of these results for intervention are discussed.

A New Look at the Psychometrics of the Parenting Scale Through the Lens of Item Response Theory

Lorber, M. F., Xu, S., Slep, A. M., Bulling, L., & O’Leary, S. G. (n.d.).

Publication year

2014

Journal title

Journal of Clinical Child and Adolescent Psychology

Volume

43

Issue

4

Page(s)

613-626
Abstract
Abstract
The psychometrics of the Parenting Scale's Overreactivity and Laxness subscales were evaluated using item response theory (IRT) techniques. The IRT analyses were based on 2 community samples of cohabiting parents of 3- to 8-year-old children, combined to yield a total sample size of 852 families. The results supported the utility of the Overreactivity and Laxness subscales, particularly in discriminating among parents in the mid to upper reaches of each construct. The original versions of the Overreactivity and Laxness subscales were more reliable than alternative, shorter versions identified in replicated factor analyses from previously published research and in IRT analyses in the present research. Moreover, in several cases, the original versions of these subscales, in comparison with the shortened versions, exhibited greater 6-month stabilities and correlations with child externalizing behavior and couple relationship satisfaction. Reliability was greater for the Laxness than for the Overreactivity subscale. Item performance on each subscale was highly variable. Together, the present findings are generally supportive of the psychometrics of the Parenting Scale, particularly for clinical research and practice. They also suggest areas for further development.

Interrater agreement statistics with skewed data: Evaluation of alternatives to Cohen's kappa

Xu, S., & Lorber, M. F. (n.d.).

Publication year

2014

Journal title

Journal of consulting and clinical psychology

Volume

82

Issue

6

Page(s)

1219-1227
Abstract
Abstract
Objective: In this study, we aimed to evaluate interrater agreement statistics (IRAS) for use in research on low base rate clinical diagnoses or observed behaviors. Establishing and reporting sufficient interrater agreement is essential in such studies. Yet the most commonly applied agreement statistic, Cohen's, has a well known sensitivity to base rates that results in a substantial penalization of interrater agreement when behaviors or diagnoses are very uncommon, a prevalent and frustrating concern in such studies. Method: We performed Monte Carlo simulations to evaluate the performance of 5 of κ's alternatives (Van Eerdewegh's V, Yule's Y, Holley and Guilford's G, Scott's π, and Gwet's AC1), alongside κ itself. The simulations investigated the robustness of these IRAS to conditions that are common in clinical research, with varying levels of behavior or diagnosis base rate, rater bias, observed interrater agreement, and sample size. Results: When the base rate was 0.5, each IRAS provided similar estimates, particularly with unbiased raters. G was the least sensitive of the IRAS to base rates. Conclusions: The results encourage the use of the G statistic for its consistent performance across the simulation conditions. We recommend separately reporting the rates of agreement on the presence and absence of a behavior or diagnosis alongside G as an index of chance corrected overall agreement.

Noxious family environments in relation to adult and childhood caries

Lorber, M. F., Slep, A. M., Heyman, R. E., Xu, S., Dasanayake, A. P., & Wolff, M. S. (n.d.).

Publication year

2014

Journal title

Journal of the American Dental Association

Volume

145

Issue

9

Page(s)

924-930
Abstract
Abstract
Background. The authors tested hypotheses that more noxious family environments are associated with poorer adult and child oral health. Methods. A community sample of married or cohabiting couples (N = 135) and their elementary school-aged children participated. Dental hygienists determined the number of decayed, missing and filled surfaces via oral examination. Subjective oral health impacts were measured by means of questionnaires completed by the parents and children. The parents completed questionnaires about interparental and parent-to-child physical aggression (for example, pushing) and emotional aggression (for example, derision), as well as harsh discipline. Observers rated the couples' hostile behavior in laboratory interactions. Results. The extent of women's and men's caries experience was associated positively with their partners' levels of overall noxious behavior toward them. The extent of children's caries experience was associated positively with the level of their mothers' emotional aggression toward their partners. Conclusions. Noxious family environments may be implicated in compromised oral health. Future research that replicates and extends these findings can provide the foundation to translate them into preventive interventions. Practical Implications. Noxious family environments may help explain the limitations of routine oral health preventive strategies. Interprofessional strategies that also address the family environment ultimately may prove to be more effective than are single modality approaches.

On Fitting a Multivariate Two-Part Latent Growth Model

Xu, S., Blozis, S. A., & Vandewater, E. A. (n.d.).

Publication year

2014

Journal title

Structural Equation Modeling

Volume

21

Issue

1

Page(s)

131-148
Abstract
Abstract
A 2-part latent growth model can be used to analyze semicontinuous data to simultaneously study change in the probability that an individual engages in a behavior, and if engaged, change in the behavior. This article uses a Monte Carlo (MC) integration algorithm to study the interrelationships between the growth factors of 2 variables measured longitudinally where each variable can follow a 2-part latent growth model. A SAS macro implementing Mplus is developed to estimate the model to take into account the sampling uncertainty of this simulation-based computational approach. A sample of time-use data is used to show how maximum likelihood estimates can be obtained using a rectangular numerical integration method and an MC integration method.

Causal Inference in Latent Class Analysis

Lanza, S. T., Coffman, D. L., & Xu, S. (n.d.).

Publication year

2013

Journal title

Structural Equation Modeling

Volume

20

Issue

3

Page(s)

361-383
Abstract
Abstract
The integration of modern methods for causal inference with latent class analysis (LCA) allows social, behavioral, and health researchers to address important questions about the determinants of latent class membership. In this article, 2 propensity score techniques, matching and inverse propensity weighting, are demonstrated for conducting causal inference in LCA. The different causal questions that can be addressed with these techniques are carefully delineated. An empirical analysis based on data from the National Longitudinal Survey of Youth 1979 is presented, where college enrollment is examined as the exposure (i.e., treatment) variable and its causal effect on adult substance use latent class membership is estimated. A step-by-step procedure for conducting causal inference in LCA, including multiple imputation of missing data on the confounders, exposure variable, and multivariate outcome, is included. Sample syntax for carrying out the analysis using SAS and R is given in an appendix.

Preadolescent drug use resistance skill profiles, substance use, and substance use prevention

Hopfer, S., Hecht, M. L., Lanza, S. T., Tan, X., & Xu, S. (n.d.).

Publication year

2013

Journal title

Journal of Primary Prevention

Volume

34

Issue

6

Page(s)

395-404
Abstract
Abstract
The aims of the current study were threefold: (1) specify the skills component of social influence prevention interventions for preadolescents, (2) examine the relationship between resistance skill profiles and substance use among preadolescents, and (3) evaluate whether subgroups of preadolescents based on their resistance skills and refusal confidence may be differentially impacted by the kiR prevention program. Latent class analysis showed a four-class model of 5th grader resistance skill profiles. Approximately half of preadolescents (53 %) were familiar with four prototypical resistance skills and showed confidence to apply these skills in real-world settings (highly competent profile); 15 % were familiar with resistance skills but had little confidence (skillful profile); 18 % were confident yet had little knowledge (confident profile); while 15 % had low knowledge and confidence (low competence profile). These skill profiles significantly predicted 8th grade recent substance use (2LL = -2,262.21, df = 3, p = .0005). As predicted by theory, the highly competent skill profile reported lower mean recent substance use than the population sample mean use. Latent transition analysis showed that although patterns of transiting into the highly competent skill profile over time were observed in the expected direction, this pattern was not significant when comparing treatment and control. Identifying skill profiles that predict recent substance use is theoretically consistent and has important implications for healthy and substance-free development.

Sensitivity Analysis of Multiple Informant Models When Data Are Not Missing at Random

Blozis, S. A., Ge, X., Xu, S., Natsuaki, M. N., Shaw, D. S., Neiderhiser, J. M., Scaramella, L. V., Leve, L. D., & Reiss, D. (n.d.).

Publication year

2013

Journal title

Structural Equation Modeling

Volume

20

Issue

2

Page(s)

283-298
Abstract
Abstract
Missing data are common in studies that rely on multiple informant data to evaluate relationships among variables for distinguishable individuals clustered within groups. Estimation of structural equation models using raw data allows for incomplete data, and so all groups can be retained for analysis even if only 1 member of a group contributes data. Statistical inference is based on the assumption that data are missing completely at random or missing at random. Importantly, whether or not data are missing is assumed to be independent of the missing data. A saturated correlates model that incorporates correlates of the missingness or the missing data into an analysis and multiple imputation that might also use such correlates offer advantages over the standard implementation of SEM when data are not missing at random because these approaches could result in a data analysis problem for which the missingness is ignorable. This article considers these approaches in an analysis of family data to assess the sensitivity of parameter estimates and statistical inferences to assumptions about missing data, a strategy that could be easily implemented using SEM software.

Sensitivity analysis of mixed models for incomplete longitudinal data

Xu, S., & Blozis, S. A. (n.d.).

Publication year

2011

Journal title

Journal of Educational and Behavioral Statistics

Volume

36

Issue

2

Page(s)

237-256
Abstract
Abstract
Mixed models are used for the analysis of data measured over time to study population-level change and individual differences in change characteristics. Linear and nonlinear functions may be used to describe a longitudinal response, individuals need not be observed at the same time points, and missing data, assumed to be missing at random (MAR), may be handled. While the mechanism giving rise to the missing data cannot be determined by the observations, the sensitivity of parameter estimates to missing data assumptions can be studied, for example, by fitting multiple models that make different assumptions about the missing data process. Sensitivity analysis of a mixed model that may include nonlinear parameters when some data are missing is discussed. An example is provided.

Latent curve models: A structural equation perspective

Blozis, S. A., Cho, Y., & Xu, V. S. (n.d.).

Publication year

2010

Journal title

Sociological Methods and Research

Volume

39

Page(s)

297

Contact

sx5@nyu.edu 708 Broadway 7FL New York, NY, 10003