Evaluating the Effectiveness of the Stimulus Pairing Observation Procedure and Multiple Exemplar Instruction on Tact and Listener Responses in Children with Autism

The Analysis of Verbal Behavior - The stimulus pairing observation procedure (SPOP) combined with multiple exemplar instruction (MEI) has been shown to be effective with typically developing...     

Potential impact of COVID-19 on ongoing clinical trials: a simulation study with the neurological Yale Global Tic Severity Scale based on the CANNA-TICS study

The COVID-19 pandemic has manifold impacts on clinical trials. In response, drug regulatory agencies and public health bodies have issued guidance on how to assess potential impacts on ongoing clinical trials and stress the importance of a risk-assessment as a pre-requisite for modifications to the clinical trial conduct. This article presents a simulation study to assess the impact on the power of an ongoing clinical trial without the need to unblind trial data and compromise trial integrity. In the context of the CANNA-TICS trial, investigating the effect of nabiximols on reducing the total tic score of the Yale Global Tic Severity Scale (YGTSS-TTS) in patients with chronic tic disorders and Tourette syndrome, the impact of the two COVID-19 related intercurrent events handled by a treatment policy strategy is investigated using a multiplicative and additive data generating model. The empirical power is examined for the analysis of the YGTSS-TTS as a continuous and dichotomized endpoint using analysis techniques adjusted and unadjusted for the occurrence of the intercurrent event. In the investigated scenarios, the simulation studies showed that substantial power losses are possible, potentially making sample size increases necessary to retain sufficient power. However, we were also able to identify scenarios with only limited loss of power. By adjusting for the occurrence of the intercurrent event, the power loss could be diminished to different degrees in most scenarios. In summary, the presented risk assessment approach may support decisions on trial modifications like sample size increases, while maintaining trial integrity.     

Effects of Lactation on Post-partum Amenorrhoea: Re-estimation Using Data from a Longitudinal Study in Guatemala

In this paper we re-estimate the effects of breastfeeding patterns on the timing of resumption of menses after controlling for maternal nutrition and maternal stressor variables. The analysis shows that simple hazard models, used on data from a longitudinal study in Guatemala, provide estimates of effects on timing of resumption of menstruation that are (a) comparable to others discussed in the recent literature and (b) generally consistent with hypotheses relating patterns of lactation, maternal nutritional status, and maternal stressors to processes that accelerate (decelerate) resumption of anovulatory cycles.     

Childhood Mortality Estimates Using the Preceding Birth Technique: Some Applications and Extensions

The Preceding Birth Technique has proved to be a simple and effective way of estimating mortality during the first two years of life when the question on the survival of the preceding child is asked at the time of a subsequent delivery. This article shows first that earlier worries about significant biases in the estimates are unfounded. Amongst the possible sources of bias considered are: the link between birth-interval length and child survival; the effects of birth intervals differing from 30 months; and the contribution of other systematic biases, such as the omission of all reports on the survival of a woman's last child. Results from a trial in the maternity clinics in Bamako, Mali are presented to illustrate both practical aspects of the method and selection effects by age and parity. A strong association between the survival chances of the succession of children born to one mother emerges. The second part of the article describes how the method can be applied more widely by asking the key questions at times other than a subsequent delivery. Adjustment factors are developed to correct for the biases introduced when the sample includes only mothers whose last-born children are alive at interview.Finally, some examples are given of recent use of the question on the survival of the preceding child in household surveys.     

Economic Swings and Demographic Changes in the History of Latin America

In this paper we study the effects of short-term fluctuations in indicators of economic well-being on selected demographic response such as births, marriages and deaths at age intervals in eleven Latin American countries between 1910 and 1990. We use conventional distributed lag models to assess the magnitude and direction of effects and test a variety of hypotheses some of which have been posed to hold in Western Europe and others that are more specific and tailored to the Latin American context. We also compare the magnitude and direction of effects obtained among these countries with those obtained for pre-industrial Europe and uncover the existence of broadly similar patterns.