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In this paper, the extended Rasch model for dichotomously scored items is derived from the general multivariate Bernoulli distribution. The necessary and sufficient conditions for the multivariate Bernoulli distribution to be equal to the extended Rasch model provide a new loglinear representation of the extended Rasch model. Conditions are also given under which the extended Rasch model is equal to the random effects Rasch model, and it is shown under what conditions the extended Rasch model is equal to a random effects Rasch model in which the underlying variable has a normal distribution. In addition, alternative models for the construction of likelihood ratio tests are proposed. One of these alternative models is Haberman's extended interaction model. Furthermore, it is shown how both the SPSS and SAS programs can be used to estimate and test loglinear representations of extended Rasch models.

This article shows that the mean and covariance structure of the predetermined autoregressive latent trajectory (ALT) model are very flexible. As a result, the shape of the modeled growth curve can be quite different from what one might expect at first glance. This is illustrated with several numerical examples that show that, for example, a linear trajectory might be present among the model predicted scores even though no latent change parameter was included in the model. In addition, 2 examples are given that show that the predetermined ALT model can fit to data generated by models with model structures that are rather different from that of the ALT model itself. The practical relevance of these findings is demonstrated using an empirical example. We end by providing recommendations for researchers considering the use of the predetermined ALT model.

This study investigated traumatic stress symptoms in severely burned survivors of two fire disasters and two comparison groups of patients with "non-disaster" burn injuries, as well as risk factors associated with acute and chronic stress symptoms. Patients were admitted to one out of eight burn centers in The Netherlands or Belgium. The Impact of Event Scale (IES) was administered to 61 and 33 survivors respectively of two fire disasters and 54 and 57 patients with "non-disaster" burn etiologies at 2 weeks, 3, 6, 12 and 24 months after the event. We used latent growth modeling (LGM) analyses to investigate the stress trajectories and predictors in the two disaster and two comparison groups. The results showed that initial traumatic stress reactions in disaster survivors with severe burns are more intense and prolonged during several months relative to survivors of "non-disaster" burn injuries. Excluding the industrial fire group, all participants' symptoms on average decreased over the two year period. Burn severity, peritraumatic anxiety and dissociation predicted the long-term negative outcomes only in the industrial fire group. In conclusion, fire disaster survivors appear to experience higher levels of traumatic stress symptoms on the short term, but the long-term outcome appears dependent on factors different from the first response. Likely, the younger age, and several beneficial post-disaster factors such as psychosocial aftercare and social support, along with swift judicial procedures, contributed to the positive outcome in one disaster cohort.

Adult attachment dimensions as well as the personality trait neuroticism have been shown to be related to psychological adjustment after bereavement. No investigations so far have studied the relative contribution of these constructs to grief and depression. In our study of 219 bereaved parents, the two adult attachment dimensions, attachment anxiety and attachment avoidance, were compared to the personality trait neuroticism in predicting psychological adjustment. The attachment dimensions explained a unique part over and above neuroticism, but contrary to expectations, neuroticism explained more variance than attachment dimensions. Implications are discussed.

Null hypothesis testing (NHT) is the most commonly used tool in empirical psychological research even though it has several known limitations. It is argued that since the hypotheses evaluated with NHT do not reflect the research-question or theory of the researchers, conclusions from NHT must be formulated with great modesty, that is, they cannot be stated in a confirmative way. Since confirmation or theory evaluation is, however, what researchers often aim for, we present an alternative approach that is based on the specification of explicit, informative statistical hypotheses. The statistical approach for the evaluation of these hypotheses is a Bayesian model-selection procedure. A non-technical explanation of the Bayesian approach is provided and it will be shown that results obtained with this method give more direct answers to the questions asked and are easier to interpret. An additional advantage of the offered possibility to formulate and evaluate informative hypotheses is that it stimulates researchers to more carefully think through and specify their expectations. © International Society for the Study of Behavioural Development 2011.