Latent Markov latent trait analysis for exploring measurement model changes in intensive longitudinal data

Drawing inferences about dynamics of psychological constructs from intensive longitudinal data requires the measurement model (MM)-indicating how items relate to constructs-to be invariant across subjects and time-points. When assessing subjects in their daily life, however, there may be multiple MMs, for instance, because subjects differ in their item interpretation or because the response style of (some) subjects changes over time. The recently proposed "latent Markov factor analysis" (LMFA) evaluates (violations of) measurement invariance by classifying observations into latent "states" according to the MM underlying these observations such that MMs differ between states but are invariant within one state. However, LMFA is limited to normally distributed continuous data and estimates may be inaccurate when applying the method to ordinal data (e.g., from Likert items) with skewed responses or few response categories. To enable researchers and health professionals with ordinal data to evaluate measurement invariance, we present "latent Markov latent trait analysis" (LMLTA), which builds upon LMFA but treats responses as ordinal. Our application shows differences in MMs of adolescents' affective well-being in different social contexts, highlighting the importance of studying measurement invariance for drawing accurate inferences for psychological science and practice and for further understanding dynamics of psychological constructs

How I explore ... the skin functional involvement in scleroderma

peer reviewedScleroderma refers to distinct clinical presentations sharing in common a sclerotic process most often clinically obvious on the skin. The involvement possibly affects the skin alone in morphea or in combination with internal lesions in systemic sclerosis. Some objective and non-invasive functional assessments are useful for better appreciating the severity and evolution of the disease, as well as to monitor the therapeutic efficacy. In this endeavour, in vivo measurements of the skin mechanical properties are unsurprisingly informative

The dire disregard of measurement invariance testing in psychological science

In psychological science, self-report scales are widely used to compare means in targeted latent constructs across time points, groups, or experimental conditions. For these scale mean comparisons (SMC) to be meaningful and unbiased, the scales should be measurement invariant across the compared time points or (experimental) groups. Measurement invariance (MI) testing checks whether the latent constructs are measured equivalently across groups or time points. Since MI is essential for meaningful comparisons, we conducted a systematic review to check whether MI is taken seriously in psychological research. Specifically, we sampled 426 psychology articles with openly available data that involved a total of 918 SMCs to (1) investigate common practices in conducting and reporting of MI testing, (2) check whether reported MI test results can be reproduced, and (3) conduct MI tests for the SMCs that enabled sufficiently powerful MI testing with the shared data. Our results indicate that (1) 4% of the 918 scales underwent MI testing across groups or time and that these tests were generally poorly reported, (2) none of the reported MI tests could be successfully reproduced, and (3) of 161 newly performed MI tests, a mere 46 (29%) reached sufficient MI (scalar invariance), and MI often failed completely (89; 55%). Thus, MI tests were rarely done and poorly reported in psychological studies, and the frequent violations of MI indicate that reported group differences cannot be solely attributed to group differences in the latent constructs. We offer recommendations on reporting MI tests and improving computational reproducibility practices

Latent Markov Latent Trait Analysis for Exploring Measurement Model Changes in Intensive Longitudinal Data

Drawing inferences about dynamics of psychological constructs from intensive longitudinal data requires the measurement model (MM)—indicating how items relate to constructs—to be invariant across subjects and time-points. When assessing subjects in their daily life, however, there may be multiple MMs, for instance, because subjects differ in their item interpretation or because the response style of (some) subjects changes over time. The recently proposed “latent Markov factor analysis” (LMFA) evaluates (violations of) measurement invariance by classifying observations into latent “states” according to the MM underlying these observations such that MMs differ between states but are invariant within one state. However, LMFA is limited to normally distributed continuous data and estimates may be inaccurate when applying the method to ordinal data (e.g., from Likert items) with skewed responses or few response categories. To enable researchers and health professionals with ordinal data to evaluate measurement invariance, we present “latent Markov latent trait analysis” (LMLTA), which builds upon LMFA but treats responses as ordinal. Our application shows differences in MMs of adolescents’ affective well-being in different social contexts, highlighting the importance of studying measurement invariance for drawing accurate inferences for psychological science and prac

In vitro production of bovine embryos derived from individual donors in the Corral® dish

Background: Since the identity of the embryo is of outmost importance during commercial in vitro embryo production, bovine oocytes and embryos have to be cultured strictly per donor. Due to the rather low yield of oocytes collected after ovum pick-up (OPU) per individual cow, oocyte maturation and embryo culture take place in small groups, which is often associated with inferior embryo development. The objective of this study was to improve embryonic development in small donor groups by using the Corral (R) dish. This commercial dish is designed for human embryo production. It contains two central wells that are divided into quadrants by a semi-permeable wall. In human embryo culture, one embryo is placed per quadrant, allowing individual follow-up while embryos are exposed to a common medium. In our study, small groups of oocytes and subsequently embryos of different bovine donors were placed in the Corral (R) dish, each donor group in a separate quadrant. Results: In two experiments, the Corral (R) dish was evaluated during in vitro maturation (IVM) and/or in vitro culture (IVC) by grouping oocytes and embryos of individual bovine donors per quadrant. At day 7, a significantly higher blastocyst rate was noted in the Corral (R) dish used during IVM and IVC than when only used during IVM (12.9% +/- 2.10 versus 22.8% +/- 2.67) (P < 0.05). However, no significant differences in blastocyst yield were observed anymore between treatment groups at day 8 post insemination. Conclusions: In the present study, the Corral (R) dish was used for in vitro embryo production (IVP) in cattle; allowing to allocate oocytes and/or embryos per donor. As fresh embryo transfers on day 7 have higher pregnancy outcomes, the Corral (R) dish offers an added value for commercial OPU/IVP, since a higher blastocyst development at day 7 is obtained when the Corral (R) dish is used during IVM and IVC

Reciprocity as a foundation of financial economics

This paper argues that the subsistence of the fundamental theorem of contemporary financial mathematics is the ethical concept ‘reciprocity’. The argument is based on identifying an equivalence between the contemporary, and ostensibly ‘value neutral’, Fundamental Theory of Asset Pricing with theories of mathematical probability that emerged in the seventeenth century in the context of the ethical assessment of commercial contracts in a framework of Aristotelian ethics. This observation, the main claim of the paper, is justified on the basis of results from the Ultimatum Game and is analysed within a framework of Pragmatic philosophy. The analysis leads to the explanatory hypothesis that markets are centres of communicative action with reciprocity as a rule of discourse. The purpose of the paper is to reorientate financial economics to emphasise the objectives of cooperation and social cohesion and to this end, we offer specific policy advice

Visceral Artery Aneurysms in Liver Transplant Candidates and in Patients after Liver Transplantation

There are only few reviews concerning visceral aneurysms in cirrhotics, and a small number of papers on visceral aneurysms in liver transplant patients. The present paper investigates this condition in both groups of patients in a 10-year-retrospective study

The economics of debt clearing mechanisms

We examine the evolution of decentralized clearinghouse mechanisms from the 13th to the 18th century; in particular, we explore the clearing of non- or limitedtradable debts like bills of exchange. We construct a theoretical model of these clearinghouse mechanisms, similar to the models in the theoretical matching literature, and show that specific decentralized multilateral clearing algorithms known as rescontre, skontrieren or virement des parties used by merchants were efficient in specific historical contexts. We can explain both the evolutionary self-organizing emergence of late medieval and early modern fairs, and its robustness during the 17th and 18th century