To illuminate individual differences in the development of attention-deficit hyperactivity disorder (ADHD) symptoms in the general population, psychometric measures are needed that can capture general population-level symptom variation reliably, validly, and comparably from childhood through to the transition to adulthood. The ADHD subscale of the…

First-order theory of mind (ToM) development has shown to conform to a Guttman scale, with desire reasoning developing before belief reasoning. There have been attempts to test for internal consistency and scalability in advanced ToM, but not over a broad age range and only with a limited set of tasks. This 2-year longitudinal study (N = 155;…

Although most psychological assessments are based on measures related to an individual's average level of performance, it has been proposed that measures of variability around one's average may provide unique individual difference information and have clinical significance. The current study investigated properties of within-person variability in…

Objective: This article first summarizes key research findings from the Pittsburgh Youth Study from 1987 to the present, and focuses on delinquency in 1,517 young men who have been followed up from late childhood into their 20s. Second, the article addresses how indicators of self-control prospectively predict later offending, and whether the…

In this study, the authors examined the psychometric properties and criterion validity of a newly developed battery of tasks that were designed to assess executive function (EF) abilities in early childhood. The battery was included in the 36-month assessment of the Family Life Project (FLP), a prospective longitudinal study of 1,292 children…

Three important methods areas of multivariate analysis that are not always thought of in terms of latent variable constructs, but for which latent variable modeling can be used to great advantage, are discussed. These methods are: (1) random coefficients describing individual differences in growth; (2) unobserved variables corresponding to missing…

Examined psychometric properties of self-perception scales of the Berkeley Puppet Interview (BPI) with children at preschool, kindergarten, and first grade. Found that young children have a multidimensional self-concept that can be reliably measured. The BPI was sensitive to normative change and individual differences. Support for validity was…

It has been hypothesized that college students develop differently in various areas of experience, that they learn to deal with interpersonal relationships early in their college experience, but that they may not have time to develop leisure interests. Instruments designed to assess growth on three of Chickering's student development vectors…

Individual differences in academic success were investigated in a geographically defined whole-population sample of very preterm children with a gestational age of less than 32 weeks or a birth weight of less than 1500 gm. The sample consisted of 264 very preterm children (75.6% of German-speaking survivors) and 264 controls matched for gender,…