Longitudinal data from a large sample of twins participating in the Netherlands Twin Register (n = 42,827, age range 3-16) were analyzed to investigate the genetic and environmental contributions to childhood aggression. Genetic auto-regressive (simplex) models were used to assess whether the same genes are involved or whether new genes come into…

Background: We examined the longitudinal trajectory of substance use (binge drinking, marijuana use, and cocaine use) in relation to self-esteem from adolescence to young adulthood. Methods: Generalized estimating equation models were fit using SAS to investigate changes in the relation between self-esteem and each substance use (binge drinking,…

Purpose: We assess farm technology adoption in an integrated analysis of social networks and innovation in plantain production in Ghana. The paper explores the strength of social networks in the agricultural innovation systems (AISs) and the effect of AISs on adoption of improved farm technology. Methodology/Approach: The paper uses social network…

We examined the relations of short-term memory (STM), metalinguistic awareness (phonological, morphological, and orthographic awareness), and rapid automatized naming (RAN) to word reading in Korean, a language with a relatively transparent orthography. STM, metalinguistic awareness, and RAN have been shown to be important to word reading, but the…

Within this "Adult Education Quarterly" ("AEQ") forum, the authors call for a dialogue and examination of research methods in the field of adult and continuing education. Using the article by Boeren as a starting point, the authors analyze both qualitative and quantitative research trends and advocate for more methodological…

The literature on Automated Essay Scoring (AES) systems has provided useful validation frameworks for any assessment that includes AES scoring. Furthermore, evidence for the scoring fidelity of AES systems is accumulating. Yet questions remain when appraising the scoring performance of AES systems. These questions include: (a) which essays are…

The domain model is an essential part of an adaptive learning system. For each educational course, it involves educational content and semantics, which is also viewed as a form of conceptual metadata about educational content. Due to the size of a domain model, manual domain model creation is a challenging and demanding task for teachers or…

The fit of cognitive diagnostic models (CDMs) to response data needs to be evaluated, since CDMs might yield misleading results when they do not fit the data well. Limited-information statistic M[subscript 2] and the associated root mean square error of approximation (RMSEA[subscript 2]) in item factor analysis were extended to evaluate the fit of…

We examined change in test-taking effort over the course of a three-hour, five test, low-stakes testing session. Latent growth modeling results indicated that change in test-taking effort was well-represented by a piecewise growth form, wherein effort increased from test 1 to test 4 and then decreased from test 4 to test 5. There was significant…

Many ways can be done to address the problem of students, one of them involving the students themselves (peer counselor). It required a standard model that can be applied by students as guidelines for the implementation of the guidance. Validity of the module it must be done according to the rules of various scientific tests. State University of…

An important concern when planning research studies is to obtain maximum precision of an estimate of a treatment effect given a budget constraint. When research designs have a "multilevel" or "hierarchical" structure changes in sample size at different levels of the design will impact precision differently. Furthermore, there…

Equating methods make use of an appropriate transformation function to map the scores of one test form into the scale of another so that scores are comparable and can be used interchangeably. The equating literature shows that the ways of judging the success of an equating (i.e., the score transformation) might differ depending on the adopted…

It is self-evident (and well supported in the literature) that the culture of an organization is an important aspect of how successful an organization is at meeting its goals. What is less evident is what the elements of the culture of an organization are; how can they be quantified; and how can we adjust them in a manner that will impact its…

In the analysis of causal effects in non-experimental studies, conditioning on observable covariates is one way to try to reduce unobserved confounder bias. However, a developing literature has shown that conditioning on certain covariates may increase bias, and the mechanisms underlying this phenomenon have not been fully explored. We add to the…

In meta-analysis, the random-effects model is often used to account for heterogeneity. The model assumes that heterogeneity has an additive effect on the variance of effect sizes. An alternative model, which assumes multiplicative heterogeneity, has been little used in the medical statistics community, but is widely used by particle physicists. In…