Determining sample size requirements for structural equation modeling (SEM) is a challenge often faced by investigators, peer reviewers, and grant writers. Recent years have seen a large increase in SEMs in the behavioral science literature, but consideration of sample size requirements for applied SEMs often relies on outdated rules-of-thumb. This study used Monte Carlo data simulation techniques to evaluate sample size requirements for common applied SEMs. Across a series of simulations, we systematically varied key model properties, including number of indicators and factors, magnitude of factor loadings and path coefficients, and amount of missing data. We investigated how changes in these parameters affected sample size requirements with respect to statistical power, bias in the parameter estimates, and overall solution propriety. Results revealed a range of sample size requirements (i.e., from 30 to 460 cases), meaningful patterns of association between parameters and sample size, and highlight the limitations of commonly cited rules-of-thumb. The broad “lessons learned” for determining SEM sample size requirements are discussed.

Background: Frailty is a key determinant of clinical outcomes. We sought to describe frailty among U.S. Veterans and its association with mortality. Methods: Nationwide retrospective cohort study of regular Veterans Affairs (VA) users, aged at least 65 years in 2002–2012, followed through 2014, using national VA administrative and Medicare and Medicaid data. A frailty index (FI) for VA (VA-FI) was calculated using the cumulative deficit method. Thirty-one age-related deficits in health from diagnostic and procedure codes were included and were updated biennially. Survival analysis assessed associations between VA-FI and mortality. Results: A VA-FI was calculated for 2,837,152 Veterans over 10 years. In 2002, 35.5% were non-frail (FI = 0–0.10), 32.6% were pre-frail (FI = 0.11–0.20), 18.9% were mildly frail (FI = 0.21–0.30), 8.7% were moderately frail (FI = 0.31–0.40), and 4.3% were severely frail (FI > 0.40). From 2002 to 2012, the prevalence of moderate frailty increased to 12.7%and severe frailty to 14.1%. Frailty was strongly associated with survival and was independent of age, sex, race, and smoking; the VA-FI better predicted mortality than age alone. Although prevalence of frailty rose over time, compared to non-frail Veterans, 2 years’ hazard ratios (95% confidence intervals) for mortality declined from a peak in 2004 of 2.01 (1.97–2.04), 3.49 (3.44–3.55), 5.88 (5.79–5.97), and 10.39 (10.23–10.56) for pre-frail, mildly, moderately, and severely frail, respectively, to 1.51 (1.49–1.53), 2.36 (2.33–2.39), 3.68 (3.63–3.73), 6.62 (6.53–6.71) in 2012. At every frailty level, risk of mortality was lower for women versus men and higher for blacks versus whites. Conclusions: Frailty affects at least 3 of every 10 U.S. Veterans aged 65 years and older, and is strongly associated with mortality. The VA-FI could be used to more accurately estimate life expectancy and individualize care for Veterans.

Prior research using the Brief Form of the Multidimensional Personality Questionnaire (MPQ-BF; Patrick, Curtin, & Tellegen, 2002) has shown evidence of 3 temperament-based subtypes--termed internalizing, externalizing, and simple PTSD--among individuals with symptoms of posttraumatic stress disorder (PTSD; Miller, Greif, & Smith, 2003). This study sought to replicate and extend research in this area by conducting a latent profile analysis of higher order temperament scales from the MPQ-BF using a new sample of 208 veterans with symptoms of PTSD. Results suggest that a 3-class solution reflecting internalizing, externalizing, and simple subtypes of posttraumatic psychopathology provided the best fit to the data. The externalizing subtype was characterized by features of antisocial, borderline, histrionic, and narcissistic personality disorders on the International Personality Disorder Examination (Loranger, 1999) as well as low levels of constraint and high levels of negative emotionality on the MPQ-BF. In contrast, individuals in the internalizing class exhibited features of schizoid and avoidant personality disorders, low levels of positive emotionality, and high levels of negative emotionality. The simple subtype was defined by low levels of comorbid personality disorder features and relatively normal personality profiles. Findings support the reliability of this typology and support the relevance of the internalizing and externalizing model to the structure of personality disorders.