On the lack of comonotonicity between likert scores and Rasch-based measures

The Rating Scale Model (RSM) and the Partial Credit Model (PCM) are fairly well-known examples of Rasch models for polytomously scored items. In addition to a number of threshold parameters, both the models contain two scalar parameters characterizing item and person location on a common interval-level scale. The rank order of items and persons defined by the Likert summative scores (i.e. the raw total scores) is compared with that obtained from the Rasch-based measures (i.e. the maximum likelihood estimates of person and item parameters). It is proved that: 1) the property of comonotonicity between Likert summative scores and Rasch-based measures holds for both the person and item parameters of the RSM; 2) the property of comonotonicity between Likert summative scores and Rasch-based measures holds for the PCM only with reference to the person parameters; 3) violations of comonotonicity are possible, for particular datasets, for the item parameters of the PCM.     

Rasch-transformed raw scores and Two-way ANOVA: a simulation analysis

This article demonstrates, through the exposition of underestimated variable effects or spurious interaction effects, the inherent inadequacy of untransformed 0-1 raw scores for analysis via Two-Way analysis of variance (ANOVA). The pioneering work in this field, conducted in the 1990's by Dr. Susan Embretson of the University of Kansas, USA, is highlighted, and the eminent suitability of Rasch transformations of 0-1 raw scores for analysis via Two-Way ANOVA is also demonstrated. In this study Monte Carlo techniques or simulations are utilized to determine the precise psychometric conditions under which differences between raw scores and Rasch transformations of those raw scores are detectable via Two-Way ANOVA. This study partially replicates Dr. Embretson's studies, and also defines the extent of underestimation and spuriousness which ensue when uniform or skewed distributions of item difficulties are used instead of normal distributions, and misfitting raw data are utilized instead of fitting data.     

Positive results receive more citations, but only in some disciplines

Negative results are commonly assumed to attract fewer readers and citations, which would explain why journals in most disciplines tend to publish too many positive and statistically significant findings. This study verified this assumption by counting the citation frequencies of papers that, having declared to “test” a hypothesis, reported a “positive” (full or partial) or a “negative” (null or negative) support. Controlling for various confounders, positive results were cited on average 32 % more often. The citation advantage, however, was unequally distributed across disciplines (classified as in the Essential Science Indicators database). Using Space Science as the reference category, the citation differential was positive and formally statistically significant only in Neuroscience & Behaviour, Molecular Biology & Genetics, Clinical Medicine, and Plant and Animal Science. Overall, the effect was significantly higher amongst applied disciplines, and in the biological compared to the physical and the social sciences. The citation differential was not a significant predictor of the actual frequency of positive results amongst the 20 broad disciplines considered. Although future studies should attempt more fine-grained assessments, these results suggest that publication bias may have different causes and require different solutions depending on the field considered.     

A comparative evaluation of methods of adjusting GPA for differences in grade assignment practices

Numerous methods have been proposed for constructing an adjusted grade point average (adjusted-GPA) that controls for differences in grading standards across college courses and departments. Compared to the raw GPA, adjusted-GPA measures are generally more predictable from preadmissions variables, such as standardized tests and high school achievement. Relative rankings of students on adjusted-GPA measures are also more consistent with their relative standings within courses. This study compared the performance of 4 polytomous IRT and 3 linear models for constructing adjusted-GPA measures. Unlike previous studies, the regression weights of predictor variables and the course parameter estimates used to compute adjusted-GPA were cross-validated. Adjusted-GPA retained noticeable advantages over raw GPA on cross-validation. The largest advantages were seen in the multiple correlation of adjusted-GPA with preadmission variables, when adjusted-GPA was constructed with the rating scale and partial credit IRT models. The cross-validity of adjusted-GPA was the weakest with the graded response model.     

Process design for the production of a ceramic-like body from recycled waste glass

The influence of fabrication variables on the sintering behaviour of a ceramic-like body containing 90% recycled waste glass was inferred from measurements of some of the fired properties (moduli of rupture and elasticity, firing shrinkage, bulk density and porosity). Interpretation of these results in terms of viscous sintering theory indicates the relative influence on the sintering behaviour of factors such as particle size and distribution, clay binder content and plasticity, pressing pressure, heating/cooling rate, firing temperature and time, thus enabling the fabrication variables to be optimized. Comparison of the physical properties of the resulting glass-based bodies with those of commercial ceramic tile bodies indicates that the glass-based bodies are very comparable with the best ceramic tiles tested, and considerably better than several commercially-produced clay-based bodies.     

Science in Africa: An overview of mainstream scientific output

The total scientific output of mainstream articles for the 15 most productive African countries for the period 1991 to 1997 was 45,080, with South Africa and Egypt publishing 15,725 and 10,433, respectively. The productions of these two top ranked countries varied little from 1991-1997 while others such as the Maghreb countries increased between 75-102%. Total contributions were mainly in the fields of Clinical Medicine (36%), Biology (17%), Chemistry (14%), and Biomedical Research (12%). Papers in international collaboration were overriding in Biomedical Research, Biology, Earth and Space Science, and Physics. Institutions in the US were the principal collaborators followed closely by those in France. This revised version was published online in June 2006 with corrections to the Cover Date.     

Self-reported driving behaviors as a function of trait anxiety

This study examined self-reported driving behaviors in 120 (Israeli) male drivers as a function of trait anxiety (TA). TA was assessed through the TA scale of the State-Trait Anxiety Inventory. For the analysis of driving behaviors, the present study used the Driver Behavior Questionnaire (DBQ) and adopted previous distinctions between four classes of behaviors within the DBQ: errors, lapses, ordinary violations and aggressive violations. Regression analyses revealed that level of TA had a significant direct positive effect on all dependent variables, suggesting riskier driving behaviors among high-anxious individuals. Significant logarithmic effects for all measures indicate that these aberrant driving behaviors increase more at increasing LTA-, than at increasing HTA-values. Consistent with the general adverse effects of anxiety on performance effectiveness, the present findings as well, are interpreted in the framework of theories which suggest that worries occupy the capacities of working memory, at the expense of the task to be performed. The positive relation between aggressive violations and TA is sought to reflect low levels of emotional adjustment among high-anxious individuals.     

Test scores,measurement, and the use of analysis of variance: an historical overview

In order to establish a firmer statistical foundation from which to draw inferences from factorial design study data, transformations of raw scores are occasionally employed in order to make their distributions more generally normal or to provide linearity. To date, few studies have been conducted to determine whether or not raw scores transformed or otherwise constitute measures for the purposes of statistical analysis. In this article, the historical development of the understanding of the term "measurement" by researchers in the social sciences is traced, and the development and use of One and Two-way ANOVA by researchers in the social sciences are presented and evaluated.     

Fuzzy quality feature monitoring model

In this paper we study the modern techniques and also present a fuzzy quality monitoring model that can be used at various stages in a production operation (the raw material input stage, between production stages). The product quality may be of several types (i.e. sensory, physical, time orientation) that sometimes may not be sensed, measured, or calculated precisely due to uncertain situations. Therefore, the γ -level fuzzy Bayesian model for quality monitoring of a manufacturing process is proposed. In order to apply the Bayesian concept, the fuzzy quality characteristics are assumed as fuzzy random variables. Using the fuzzy quality characteristics, the newly developed model calculates the risk of operation for the manufacturing process, which results in determining the out-of-control process. A numerical example is also presented to demonstrate the application of the model.     

Isotropic-sequence-order learning in a closed-loop behavioural system

The simplest form of sensor-motor control is obtained with a reflex. In this case the reflex can be interpreted as part of a closed-loop control paradigm which measures a sensor input and generates a motor reaction as soon as the sensor signal deviates from its desired (resting) state. This is a typical case of feedback control. However, reflex reactions are tardy, because they occur always only after a (for example, unpleasant) reflex-eliciting sensor event. This defines an objective problem for an organism which can only be avoided if the corresponding motor reaction is generated earlier. The goal of this study is to design a closed-loop control situation where temporal-sequence learning supersedes a tardy reflex reaction with a proactive anticipatory action. We achieve this by employing a second, earlier-occurring and causally coupled sensor event. An appropriate motor reaction to this early event prevents triggering of the original, primary reflex. Such causally coupled sensor events are common for animals, for example when smell predicts taste or when heat radiation precedes pain. We show that trying to achieve anticipatory control is a fundamentally different goal from trying to model a classical conditioning paradigm, which is an open-loop condition. To this end, we use a novel learning rule for temporal-sequence learning called isotropic-sequence-order (ISO) learning, which performs a confounded correlation between the primary sensor signal associated to the reflex and a predictive, earlier-occurring sensor input: this way the system learns the relation between the primary reflex and the earlier sensor input in order to create an earlier-occurring motor reaction. As a consequence of learning, the primary reflex will not be triggered any more, thereby permanently remaining in its desired resting state. In a robot application, we demonstrate that ISO learning can successfully solve the classical obstacle-avoidance task by learning to correlate a built-in reflex behaviour (retraction after touching) with earlier arising signals from range finders (before touching). Finally, we show that avoidance and attraction tasks can be combined in the same agent.     

From Rasch scores to regression

Rasch models provide a framework for measurement and modelling latent variables. Having measured a latent variable in a population a comparison of groups will often be of interest. For this purpose the use of observed raw scores will often be inadequate because these lack interval scale properties. This paper compares two approaches to group comparison: linear regression models using estimated person locations as outcome variables and latent regression models based on the distribution of the score.     

Modeling safe and unsafe driving behaviour

A sample of 743 Dutch drivers was queried about driving-related errors and violations, and about the frequency of their accident involvement over the past 3 years. In addition, the following risky behaviours and characteristics related to driving were measured through self-report: strategic decisions made about driving before starting a trip, attitudes related to committing violations, psychological precursors of unsafe driving (such as being tired or stressed when driving), and physical precursors of unsafe driving (suffering physical or psychological handicaps when driving). The results show that several scales have acceptable reliability coefficients, though several others are in need of improvement. Path analysis showed that an acceptable structural model could be developed to describe all empirical relationships. Considerable parts of the variance in the violations scores and the psychological precursors scores could be explained by the other model variables. In terms of predictive power, "unsafe" attitudes, physical precursors, and psychological precursors had the most impact, each explaining up to 9% of the variance in violations scores, errors scores, and/or psychological precursors scores. The way these results can be utilized in future accident prevention programs and in driver training programs are indicated, as are their implications for future research.     

Preparation of activated carbons from coffee husks utilizing FeCl3 and ZnCl2 as activating agents

Ferric chloride was used as a new activating agent, to obtain activated carbons (AC) from agro industrial waste (coffee husks). This material was compared with two samples from the same raw material: one of them activated by using the classical activating agent, zinc chloride, and the other, activated with a mixture of the two mentioned activating agents in the same mass proportion. The carbonaceous materials obtained after the activation process showed high specific surface areas (BET), with values higher than 900 m(2)g(-1). It is interesting to observe that the activation with FeCl(3) produces smaller pores compared to the activation with ZnCl(2). An important fact to emphasize in the use of FeCl(3) as activating agent is the activation temperature at 280 degrees C, which is clearly below to the temperature commonly employed for chemical or physical activation, as described in the bibliography. All the studied materials showed different behaviors in the adsorption of methylene blue dye and phenol from aqueous solutions.     

Developing examinations that use equal raw scores for cut scores

This study describes and demonstrates a set of processes for developing new forms of examinations which are intended to have equivalent cut scores in the raw score metric. This approach goes beyond the traditional Rasch-based approach which develops forms with cut scores that are equated in the logit metric. The methods described in this study can be used to create multiple forms of an assessment, all of which have the same raw score cut score (i.e., the number correct required to pass each examination form represents the same amount of the underlying construct). This paper provides an overview of equating standards, the research related specifically to pre-equating procedures, and three guidelines which can be used to achieve equal raw score cut scores. Three examples of how to use the guidelines as part of an iterative form-development process are provided using simulated data sets.     

A closer look at frailty in ESRD: Getting the measure right

Patients treated with dialysis have low levels of physical functioning and activity. Whether this translates into frailty or not may depend on how the frailty phenotype is operationalized. This is a secondary analysis of data from the Renal Exercise Demonstration Project to evaluate two methods of operationalizing the Fried phenotype for frailty: Using measured walking speed and muscle weakness (FRAILmeas) and using substitution of the Physical Function Scale (PF) from the SF‐36 questionnaire for walking speed and muscle weakness (FRAILsubst). Complete data for both measures were available for 188 hemodialysis patients. The frailty score (FRAILmeas) was the sum of criteria scores for measured gait speed, chair stand, body mass index, vitality, and physical activity. The frailty score (FRAILsubst) substituted the PF scale score (<75) as a surrogate measure for gait speed and for weakness. The frailty score ranged from 0 to 5. Scores ≥3 were categorized as frail, and <3 as not frail. The substitution of the PF score for walking speed and muscle weakness resulted in 78% of patients being categorized as frail compared to 24% using actual measured walking speed and muscle weakness (P < .001). The component of frailty that had the highest prevalence was low physical activity (average 54% of subjects). Frailty (using the FRAILmeas) was higher in patients with increasing age, female gender, and lower self‐reported PF. Frailty is highly prevalent in hemodialysis patients; however, measured constructs of the components of frailty should be used to report the frailty phenotype.     

Risk factors in road crossing among elderly pedestrians and readiness to adopt safe behavior in socio-economic comparison

This research examines the Health Promotion Behavior (HPB) models regarding elderly pedestrians’ behaviors and attitudes. We studied cognitive-psychological variables, such as risk estimation, self-efficacy and demographic variables and compared elderly pedestrians’ attitudes and behaviors in a city with higher socio-economic level (Tel Aviv) versus a city with low socio-economic level (Beer Sheva). We expected to find more problematic behaviors among elderly pedestrians in the low socio-economic city compared to the high socio-economic city, and also less feeling of self-efficacy, and lessened awareness of the risks, that leads to lessened willingness to adopt preventive behaviors. The research was conducted in two studies. The first study was based on observations on 2591 pedestrians in six similar crosswalks in both cities. It revealed that pedestrians in the high socio-economic city demonstrated safer road crossing patterns than in the low socio-economic city and that elderly pedestrians reveal safer crossing patterns than younger pedestrians. We found an interaction of location and age due to greater gap of safe behaviors of elderly and young pedestrians in the high socio-economic city than in the low socio-economic city. In Tel Aviv elderly adhere to the crossing rules much more than the young while in Beer Sheva elderly and young people are almost similar in their crossing patterns. The second study used questionnaires that have been completed by 143 elderly in both cities. The questionnaires referred to (a) demographic variables such as gender, age, marital status, education, socio-economic level, (b) variables related to the affiliation to the main culture such as migration, date of migration, knowledge in Hebrew (local language) and connectivity to media and (c) cognitive as well as psychological variables related to the decline to adopt healthy behaviors based on Schwarzer and Fuchs (1995). This part also indicated that elderly in Tel Aviv have higher awareness of risk factors on the road and their limitations as elderly pedestrians. The HPB (Pender, 1996) emphasizes the role of risk perception as a predictor of willingness to adopt preventive strategies. Moreover, elderly pedestrians in Beer Sheva compared to those in Tel Aviv estimated their ability to cross safely the streets as higher.     

Validation of the Australian Propensity for Angry Driving Scale (Aus-PADS)

The present study used a university sample to assess the test–retest reliability and validity of the Australian Propensity for Angry Driving Scale (Aus-PADS). The scale has stability over time, and convergent validity was established, as Aus-PADS scores correlated significantly with established anger and impulsivity measures. Discriminant validity was also established, as Aus-PADS scores did not correlate with Venturesomeness scores. The Aus-PADS has demonstrated criterion validity, as scores were correlated with behavioural measures, such as yelling at other drivers, gesturing at other drivers, and feeling angry but not doing anything. Aus-PADS scores reliably predicted the frequency of these behaviours over and above other study variables. No significant relationship between aggressive driving and crash involvement was observed. It was concluded that the Aus-PADS is a reliable and valid tool appropriate for use in Australian research, and that the potential relationship between aggressive driving and crash involvement warrants further investigation with a more representative (and diverse) driver sample.     

Pre-equating: a simulation study based on a large scale assessment model

Although post-equating (PE) has proven to be an acceptable method in the scaling and equating of items and forms, there are times when the turn-around period for equating and converting raw scores to scale scores is so small that PE cannot be undertaken within the prescribed time frame. In such cases, pre-equating (PrE) could be considered as an acceptable alternative. Assessing the feasibility of using item calibrations from the item bank (as in PrE) is conditioned on the equivalency of the calibrations and the errors associated with it vis a vis the results obtained via PE. This paper creates item banks over three periods of item introduction into the banks and uses the Rasch model in examining data with respect to the recovery of item parameters, the measurement error, and the effect cut-points have on examinee placement in both the PrE and PE situations. Results indicate that PrE is a viable solution to PE provided the stability of the item calibrations are enhanced by using large sample sizes (perhaps as large as full-population) in populating the item bank.     

Effect of exposure to aggressive stimuli on aggressive driving behavior at pedestrian crossings at unmarked roadways

BackgroundAggressive driving, influenced by the proneness of driving aggression, angry state and provoking situation, is adversely affecting traffic safety especially in developing countries where pedestrians frequently cross an unmarked crosswalk. Exposure to aggressive stimuli causes driving anger and aggressive driving behaviors, but the exposure effect on higher and lower aggression drivers and their cumulative changes under successive exposures need more investigation.ObjectivesAn experiment was conducted to examine (1) driving behaviors of individuals with higher and lower aggressive driving traits when approaching pedestrian crossings at unmarked roadways with and without aggressive provocation; and (2) cumulative changes of driving performance under repeated provocations.MethodWe conducted a driving simulator study with 50 participants. Trait of aggressive driving served as a between-subjects variable: participants with an Aggressive Driving Scale (ADS) total score of 30 or more (for men) or 23 or more (for women) were regarded as higher aggressive drivers; lower aggressive drivers were those individuals whose ADS total scores were 21 or less (for men) or 13 or less (for women). Exposure to aggressive stimuli (provoked vs. non-provoked condition) served as a within-subjects variable. Several aspects of the participants’ minimum driving speed, lateral distance from a simulated pedestrian, lateral deviation, and subjective measures were collected.ResultsWe found that drivers with higher aggressive driving traits were more likely to feel irritated and fail to give way for pedestrians and drove closer to pedestrians when exposed to sustained honking and improper passing compared to the non-provoked condition. This trait × state interaction only occurred when pedestrians crossed the street from the right roadway edge line. In addition, we observed an accumulation effect of exposure to aggressive stimuli on driver's aggressive behaviors at pedestrian crossings.ConclusionsEnvironmental design, law enforcement, and educational campaign may have practical value for reducing pedestrian and driver conflicts at unmarked roadways.