Although variable-oriented analyses are dominant in developmental psychopathology, researchers have championed a person-oriented approach that focuses on the individual as a totality. This view has methodological implications and various person-oriented methods have been developed to test person-oriented hypotheses. Configural frequency analysis (CFA) has been identified as a prime method for a person-oriented analysis of categorical data. CFA searches for configurations in cross-classifications and asks whether the number of observed cases is larger (CFA type) or smaller (CFA antitype) than expected under a probability model. The present study introduces a combination of CFA and model-based recursive partitioning (MOB) to test for type/antitype heterogeneity in the population. MOB CFA is well suited to detect complex moderation processes and can distinguish between subpopulation and population types/antitypes. Model specifications are discussed for first-order CFA and prediction CFA. Results from two simulation studies suggest that MOB CFA is able to detect moderation processes with high accuracy. Two empirical examples are given from school mental health research for illustrative purposes. The first example evaluates heterogeneity in student behavior types/antitypes, the second example focuses on the effect of a teacher classroom management intervention on student behavior. An implementation of the approach is provided in R.

This prospective longitudinal study examines the long-term influence of intimate partner violence (IPV) exposure in utero. We hypothesized that (a) prenatal IPV increases risk for internalizing and externalizing problems as well as for a profile of dysregulated cortisol reactivity, and (b) patterns of cortisol hyper- and hyporeactivity are differentially associated with internalizing and externalizing problems. The participants were 119 10-year-old children. Their mothers reported their IPV experiences and distress during pregnancy. Child and maternal reports of internalizing and externalizing problems as well as lifetime IPV exposure were obtained. Salivary cortisol was assessed at baseline, 20 min, and 40 min after challenge. The results partially supported our hypotheses: Exposure to IPV during pregnancy predicted child-reported internalizing and externalizing problems, mother ratings of child externalizing problems, and a profile of high cortisol secretion before and after stress challenge. The results were significant above and beyond the influence of maternal distress during pregnancy and IPV that occurred during the child's life. In addition, a profile of high cortisol secretion was associated with maternal reports of child internalizing behaviors. Findings support the growing consensus that prenatal stress can lead to lasting disruptions in adaptation and highlight the need for more longitudinal examinations of prenatal IPV exposure.

The development of paradigms, or perspectives of research takes place at the level of theory, in the domain of methodology, and in the context of existing paradigms and perspectives. The development of the person-oriented approach has made considerable progress at the level of theory. In addition, the approach has found a large number of applications. Sterba and Bauer's Keynote Article has closed a gap by discussing methodological implications of the person-oriented approach. In particular, the authors have discussed whether and, if yes, how the tenets of the person-oriented approach can be tested using tools of applied statistics popular in current empirical psychological research. Continuing this discussion, this article focuses on recent developments in all three areas. First, the importance and the implications of the concept of dimensional identity are discussed. It is argued that dimensional identity needs to be established across time and individuals for comparisons to be valid, both in person-oriented and in variable-oriented research. Second, methods not covered in Sterba and Bauer's Keynote are discussed and their application is exemplified. One focus of this discussion is on configural frequency analysis, which allows researchers to make statements about particular cells or groups of cells in cross-classifications of categorical variables. Third, person-oriented research is compared to differential psychology. It is argued that the concept of dimensional identity represents the next step in the development of a psychological subdiscipline that allows one to consider that individuals differ and develop in unique ways. These differences not only manifest in means but in any parameter, including covariance structures, and they can also manifest in the differential meaningfulness of variables for the description of individuals.

This article deals with alternative research strategies for developmental psychopathology. It argues that most applications of statistical methods in empirical research are variable centered, not person oriented. As a result, conclusions are often drawn that fail to do justice to the diverse nature of populations. It is recommended that we take seriously the importance of the implications of data aggregation. The difficulties of making inferences from a more aggregated level of analysis to a less aggregated level are explained and exemplified. We explain that a set of variables displays dimensional identity if the variable relationships remain unchanged across the levels or categories of other variables. Data examples of intelligence divergence and of Child Behavior Checklist subpopulation differences show that lack of dimensional identity can lead to incorrect conclusions. Schmitz' theorems on aggregation and the validity of results at the aggregate level for individuals are illustrated using data from a study on the development of alcoholism and discussed from a person-oriented perspective. Statistical methods suitable for person-oriented data analysis are reviewed.