Project description:BackgroundStandard setting for clinical examinations typically uses the borderline regression method to set the pass mark. An assumption made in using this method is that there are equal intervals between global ratings (GR) (e.g. Fail, Borderline Pass, Clear Pass, Good and Excellent). However, this assumption has never been tested in the medical literature to the best of our knowledge. We examine if the assumption of equal intervals between GR is met, and the potential implications for student outcomes.MethodsClinical finals examiners were recruited across two institutions to place the typical 'Borderline Pass', 'Clear Pass' and 'Good' candidate on a continuous slider scale between a typical 'Fail' candidate at point 0 and a typical 'Excellent' candidate at point 1. Results were analysed using one-sample t-testing of each interval to an equal interval size of 0.25. Secondary data analysis was performed on summative assessment scores for 94 clinical stations and 1191 medical student examination outcomes in the final 2 years of study at a single centre.ResultsOn a scale from 0.00 (Fail) to 1.00 (Excellent), mean examiner GRs for 'Borderline Pass', 'Clear Pass' and 'Good' were 0.33, 0.55 and 0.77 respectively. All of the four intervals between GRs (Fail-Borderline Pass, Borderline Pass-Clear Pass, Clear Pass-Good, Good-Excellent) were statistically significantly different to the expected value of 0.25 (all p-values < 0.0125). An ordinal linear regression using mean examiner GRs was performed for each of the 94 stations, to determine pass marks out of 24. This increased pass marks for all 94 stations compared with the original GR locations (mean increase 0.21), and caused one additional fail by overall exam pass mark (out of 1191 students) and 92 additional station fails (out of 11,346 stations).ConclusionsAlthough the current assumption of equal intervals between GRs across the performance spectrum is not met, and an adjusted regression equation causes an increase in station pass marks, the effect on overall exam pass/fail outcomes is modest.
Project description:Research on the multidimensionality of hallucination-like experiences (HLEs) can contribute to the study of psychotic risk. The Launay-Slade Hallucinations Scale-Extended (LSHS-E) is one of the most widely used tools for research in HLEs, but the correspondence of its paper and online formats has not been established yet. Therefore, we studied the factorial structure and measurement invariance between online and paper-and-pencil versions of LSHS-E in a Chilean population. Two thousand eighty-six completed the online version, and 578 students completed the original paper-and-pencil version. After matching by sex, age, civil status, alcohol and cannabis consumption, and psychiatric treatment received, we selected 543 students from each group. We conducted a confirmatory factor analysis of a four-factor model and a hierarchical model that included a general predisposition to hallucination, explaining the strong relationship between the different types of hallucinations. Both models showed a good fit to the data and were invariant between paper-and-pencil and online versions. Also, the LSHS-E has good reliability in both online and paper-and-pencil formats. This study shows that the online LSHS-E possesses psychometric properties equivalent to the paper-and-pencil version. It should be considered a valuable tool for research of psychosis determinants in the COVID-19 era.Supplementary informationThe online version contains supplementary material available at 10.1007/s12144-021-02497-7.
Project description:Most existing measures of distance between phylogenetic trees are based on the geometry or topology of the trees. Instead, we consider distance measures which are based on the underlying probability distributions on genetic sequence data induced by trees. Monte Carlo schemes are necessary to calculate these distances approximately, and we describe efficient sampling procedures. Key features of the distances are the ability to include substitution model parameters and to handle trees with different taxon sets in a principled way. We demonstrate some of the properties of these new distance measures and compare them to existing distances, in particular by applying multidimensional scaling to data sets previously reported as containing phylogenetic islands. [Metric; probability distribution; multidimensional scaling; information geometry.
Project description:Questionnaires with uniform-ordered categorical response formats are widely applied in psychology. Muraki proposed a modified graded response model accounting for the items' uniform response formats by assuming identical threshold parameters defining the category boundaries for all items. What is not well known is that there is a set of closely related models, which similarly assume identical thresholds. The present article gives a framework illustrating the differences between these models and their utility for understanding questionnaire responses in detail. The models are explained as constrained cases of a one-dimensional factor model for ordered categorical data. Furthermore, the authors show that the models can be written and fitted as structural equation models, which allows for a very flexible and general purpose use. Instructions on implementing the models in Mplus and SAS PROC NLMIXED are given.
Project description:Using detailed geocoded microdata from the British Household Panel Survey and longitudinal random-effects models, we analyse the determinants and trajectories of geographical distances between separated parents. Findings of particular note include the following: (1) post-separation linked lives, proximities and spatial constraints are characterised by important gender asymmetries; (2) the formation of new post-separation family ties (i.e. new partners and children) by fathers is linked to moves over longer distances away from the ex-partner than for mothers; (3) the distribution of pre-separation childcare responsibilities is relevant for determining post-separation proximity between parents; and (4) most variation in the distance between ex-partners occurs in the immediate period following separation (approximately the first year), suggesting that the initial conditions around separation can have long-lasting implications for the types of family life, ties and contact experienced in the years after separation.
Project description:Studies assessing the association between hunger and psychological states have been conducted in laboratory settings, or limited to persons with eating disorders. In this study, 748 community-dwelling adults (56.4% women, 60.0 ± 9.3 years) completed the Ecological Momentary Assessment four times a day (08:00, 12:00, 16:00 and 20:00) for seven days. At each assessment, respondents indicated their current hunger level, food intake, and psychological states (sad, anxious, active, lively, distracted, anhedonic, angry, slow thinking and restless). Time-lagged associations assessing the effect of hunger on subsequent psychological states 4 h later and vice-versa were assessed. Hunger intensity increased subsequent active feeling (coefficient and 95% confidence interval: 0.029 (0.007; 0.051)) and lively feeling (0.019 (0.004; 0.034)) and decreased later slow thinking (-0.016 (-0.029; -0.003)). Previous eating increased later activity (0.116 (0.025; 0.208)). Feeling active (0.050 (0.036; 0.064)), lively (0.045 (0.023; 0.067)) and restless (0.040 (0.018; 0.063)) increased later hunger intensity, while distraction (-0.039 (-0.058; -0.019)) and slow thinking (-0.057 (-0.080; -0.034)) decreased it. No association was found between hunger, food intake and negative psychological states (sadness, anxiety and anger). Conclusions: Positive psychological states and hunger influence each other, while no association was found between hunger and negative psychological states.
Project description:IntroductionAs their name suggests, 'psychedelic' (mind-revealing) compounds are thought to catalyse processes of psychological insight; however, few satisfactory scales exist to sample this. This study sought to develop a new scale to measure psychological insight after a psychedelic experience: the Psychological Insight Scale (PIS).MethodsThe PIS is a six- to seven-item questionnaire that enquires about psychological insight after a psychedelic experience (PIS-6) and accompanied behavioural changes (PIS item 7). In total, 886 participants took part in a study in which the PIS and other questionnaires were completed in a prospective fashion in relation to a planned psychedelic experience. For validation purposes, data from 279 participants were analysed from a non-specific 'global psychedelic survey' study.ResultsPrincipal components analysis of PIS scores revealed a principal component explaining 73.57% of the variance, which displayed high internal consistency at multiple timepoints throughout the study (average Cronbach's α = 0.94). Criterion validity was confirmed using the global psychedelic survey study, and convergent validity was confirmed via the Therapeutic-Realizations Scale. Furthermore, PIS scores significantly mediated the relationship between emotional breakthrough and long-term well-being.ConclusionThe PIS is complementary to current subjective measures used in psychedelic studies, most of which are completed in relation to the acute experience. Insight - as measured by the PIS - was found to be a key mediator of long-term psychological outcomes following a psychedelic experience. Future research may investigate how insight varies throughout a psychedelic process, its underlying neurobiology and how it impacts behaviour and mental health.
Project description:Based on the framework of testlet models, the current study suggests the Bayesian random block item response theory (BRB IRT) model to fit forced-choice formats where an item block is composed of three or more items. To account for local dependence among items within a block, the BRB IRT model incorporated a random block effect into the response function and used a Markov Chain Monte Carlo procedure for simultaneous estimation of item and trait parameters. The simulation results demonstrated that the BRB IRT model performed well for the estimation of item and trait parameters and for screening those with relatively low scores on target traits. As found in the literature, the composition of item blocks was crucial for model performance; negatively keyed items were required for item blocks. The empirical application showed the performance of the BRB IRT model was equivalent to that of the Thurstonian IRT model. The potential advantage of the BRB IRT model as a base for more complex measurement models was also demonstrated by incorporating gender as a covariate into the BRB IRT model to explain response probabilities. Recommendations for the adoption of forced-choice formats were provided along with the discussion about using negatively keyed items.
Project description:According to theories of embodied numerosity, processing of numerical magnitude is anchored in bodily experiences. In particular, spatial representations of number interact with movement in physical space, but it is still unclear whether the extent of the movement is relevant for this interaction. In this study, we compared spatial-numerical associations over response movements of differing spatial expansion. We expected spatial-numerical effects to increase with the extent of physical response movements. In addition, we hypothesized that these effects should be influenced by whether or not a spatial representation of numbers was presented. Adult participants performed two tasks: a magnitude classification (comparing numbers to the fixed standard 5), from which we calculated the Spatial Numerical Association of Response Codes (SNARC) effect; and a magnitude comparison task (comparing two numbers against each other), from which we calculated a relative numerical congruity effect (NCE), which describes that when two relatively small numbers are compared, responses to the smaller number are faster than responses to the larger number; and vice versa for large numbers. A SNARC effect was observed across all conditions and was not influenced by response movement extent but increased when a number line was presented. In contrast, an NCE was only observed when no number line was presented. This suggests that the SNARC effect and the NCE reflect two different processes. The SNARC effect seems to represent a highly automated classification of numbers as large or small, which is further emphasized by the presentation of a number line. In contrast, the NCE likely results from participants not only classifying numbers as small or large, but also processing their relative size within the relevant section of their mental number line representation. An additional external presentation of a number line might interfere with this process, resulting in overall slower responses. This study follows up on previous spatial-numerical training studies and has implications for future spatial-numerical trainings. Specifically, similar studies with children showed contrasting results, in that response format but not number line presentation influenced spatial-numerical associations. Accordingly, during development, the relative relevance of physical experiences and presentation format for spatial-numerical associations might change.
Project description:The psychological response to musculoskeletal injuries has been well documented, however, research on the psychological response to concussion is limited. The Profile of Mood States (POMS) and the State-Trait Anxiety Inventory (STAI) have recently been used to assess the psychological recovery of concussions. Although some studies indicate that psychological response is different for musculoskeletal injuries and concussion, there is currently not enough information to indicate this difference occurs at specific clinical milestones. The purpose of this study was to compare the psychological responses of student-athletes who have been diagnosed with a concussion to those of athletes diagnosed with musculoskeletal injuries with similar recovery duration. Fifteen collegiate athletes who sustained a musculoskeletal injury were recruited and matched with 15 previously collected concussion participants. The main outcome measures were the scores of POMS constructs: tension-anxiety, anger-hostility, fatigue-inertia, depression-dejection, vigor-activity, confusion-bewilderment, and total mood disturbance and STAI (state anxiety only). Two-way MANOVAs was run to determine the effects of group and time on POMS and STAI constructs. There were no significant interactions identified, but follow-up ANOVAs identified a main effect for time for most POMS subscales, with POMS scores improving over time in both groups. Analyses also revealed that tension-anxiety, vigor-activity and the STAI were not affected by time or group. The findings of this study, that both groups' psychological response to injury improves over time and at similar clinical milestones suggests reduction in sports and team related activities may play a substantial role in the psychological response to either concussion or musculoskeletal injury.