Following the onset of the novel coronavirus disease 2019 (COVID-19) pandemic, daily life significantly changed for the population. Accordingly, researchers interested in examining patterns of change over time may now face discontinuities around the pandemic. Researchers collecting in-person longitudinal data also had to cancel or delay data…

Spline growth modelling is a popular tool to model change processes with distinct phases and change points in longitudinal studies. Focusing on linear spline growth models with two phases and a fixed change point (the transition point from one phase to the other), we detail how to find optimal data collection designs that maximize the efficiency…

Consumption of news media can influence attitudes toward specific groups, but the influence of news media on longitudinal data collection has not yet been researched. We present a method to index media attention on a specific topic, as well as a case study on a big child sexual abuse (CSA) story and its effect on parents' attitudes toward male…

The present article aims to show how to model longitudinal change in cohort sequential data applying latent true change models using Mplus' multi-group approach. The underlying modeling ideas are described and explained in this article. As an example, change in internalizing problem behaviors between the age of 8 and 13 years is modeled and…

Romantic relationship quality in adolescence and early adulthood has often been linked to earlier parent-child relationship quality but it is possible that these links are nonlinear. Moreover, the role of social skills as mediator of associations between parent-child and romantic relations has been discussed but not rigorously tested. Using data…

Planned missing data designs allow researchers to increase the amount and quality of data collected in a single study. Unfortunately, the effect of planned missing data designs on power is not straightforward. Under certain conditions using a planned missing design will increase power, whereas in other situations using a planned missing design…

In 2003 Australia was one of the first countries to develop an integrated national policy, called the National Safe Schools Framework (NSSF), for the prevention and management of violence, bullying, and other aggressive behaviors. The effectiveness of this framework has not yet been formally evaluated. Cross-sectional data collected in 2007 from…

Using seven waves of data, collected twice a year from the 8th through the 11th grades in a low-resource community in Cape Town, South Africa, we aimed to describe the developmental trends in three specific leisure experiences (leisure boredom, new leisure interests, and healthy leisure) and substance use (cigarettes, alcohol, and marijuana)…

Many outcome variables in developmental psychopathology research are highly stable over time. In conventional longitudinal data analytic approaches such as multiple regression, controlling for prior levels of the outcome variable often yields little (if any) reliable variance in the dependent variable for putative predictors to explain. Three…