Using the Rasch measurement model to investigate the construct of motor ability in young children

This paper reports the use of a Rasch measurement model, the Extended Logistic Model of Rasch (Andrich, 1988), to explore the construct of a general motor ability in young children. Data were collected from 332 five and six year old children performing 24 motor skills, including run, hop, balance and ball skills. The data were categorised based on threshold estimates provided by the measurement model. Gender differences in performances on items were hypothesised to contribute to initial item and person misfit for the total sample. The data for boys and for girls were separated and independently analysed resulting in improved item and person fit. Two different, unidimensional scales for boys and for girls were created.     

Rasch analysis of a new construct: functional caregiving for adult children with intellectual disabilities

This research examined empirical evidence for a new construct, Functional Caregiving, which is a theory about mothers' caregiving of their adult children with intellectual disabilities. A sample of 108 biological mothers and primary caregivers rated survey items about their confidence to perform caregiving tasks. Rasch rating scale analysis found 61 items defined an empirical construct with three caregiving levels: Advocacy, Personal Caregiving, and Community. Results show item separation was 3.11 with high reliability, .91, and mother separation was 2.93 and reliability, .90. Both items and mothers showed adequate INFIT and OUTFIT values. Item invariance was confirmed between older and younger mothers, and principle components analysis of item residuals did not reveal any major dimensionality threats. Item decomposition analysis showed FC content theory to account for 58 percent of item calibration variance (R2 = .58, F = 42.3, p < .001). These results have important practical implications for health and social services, as well as family caregiving, interdisciplinary practices, and health policy development.     

Factors associated with parental safe road behaviour as a pedestrian with young children in metropolitan New South Wales, Australia

A cross-sectional population-based randomised telephone survey of parents with children aged between 5 and 12 years was conducted to investigate factors associated with safe road behaviour of parents as pedestrians with their young children in Sydney metropolitan and near by cities in New South Wales, Australia. Parental perception of the road environment as hazardous associated significantly with their safe road behaviour as pedestrian while with their children. This held true even after adjusting for the non-English speaking background and the age of the child. Knowledge of road rules, on the other hand, was not associated with parental safe road behaviour. The results of this study suggested that parental safe road behaviour require much attention in future research and in programme development. The perception of the road environment is a very important factor in motivating safe road behaviour. This should be taken into consideration in designing road safety campaigns.     

A microscopic link analysis of academic institutions within a country — the case of Israel

Links analysis proved to be very fruitful on the Web. Google's very successful ranking algorithm is based on link analysis. There are only a few studies that analyzed links qualitatively, most studies are quantitative. Our purpose was to characterize these links in order to gain a better understanding why links are created. We limited the study to the academic environment, and as a specific case we chose to characterize the interlinkage between the eight Israeli universities. This revised version was published online in June 2006 with corrections to the Cover Date.     

Geographical analysis of the academic brain drain in Italy

To study the behavior of Italian researchers living in Italy with a view to creating appropriate policies to tackle the brain drain and discourage academics from weight in driving emigrating, we constructed a survey based on a sample of 4,700 Italian researchers (assistant professors) in several universities in Italy. The outlook is far from rosy: Italian researchers are generally dissatisfied with the economic and social situation of the country. Strong family ties represent the element keeping them at home in Italy. In this regard, no particular differences were noted between the North and South of the country. In analyzing the Italian academic system we identified factors that have greater weight in driving Italian intellectual talent to emigrate: the country??s higher education system leaves all dissatisfied. Furthermore, we discovered other factors that, albeit weak, keep Italian researchers in Italy. However, one wonders how much longer family and national ties will be able to keep Italian skilled agents in Italy, and whether such dissatisfaction may jeopardize the country??s future economic development.     

Rasch techniques for detecting bias in performance assessments: an example comparing the performance of native and non-native speakers on a test of academic English

The use of common tasks and rating procedures when assessing the communicative skills of students from highly diverse linguistic and cultural backgrounds poses particular measurement challenges, which have thus far received little research attention. If assessment tasks or criteria are found to function differentially for particular subpopulations within a test candidature with the same or a similar level of criterion ability, then the test is open to charges of bias in favour of one or other group. While there have been numerous studies involving dichotomous language test items (see e.g. Chen and Henning, 1985 and more recently Elder, 1996) few studies have considered the issue of bias in relation to performance based tasks which are assessed subjectively, via analytic and holistic rating scales. The paper demonstrates how Rasch analytic procedures can be applied to the investigation of item bias or differential item functioning (DIF) in both dichotomous and scalar items on a test of English for academic purposes. The data were gathered from a pilot English language test administered to a representative sample of undergraduate students (N= 139) enrolled in their first year of study at an English-medium university. The sample included native speakers of English who had completed up to 12 years of secondary schooling in their first language (L1) and immigrant students, mainly from Asian language backgrounds, with varying degrees of prior English language instruction and exposure. The purpose of the test was to diagnose the academic English needs of incoming undergraduates so that additional support could be offered to those deemed at risk of failure in their university study. Some of the tasks included in the assessment procedure involved objectively-scored items (measuring vocabulary knowledge, text-editing skills and reading and listening comprehension) whereas others (i.e. a report and an argumentative writing task) were subjectively-scored. The study models a methodology for estimating bias with both dichotomous and scalar items using the programs Quest (Adams and Khoo, 1993) for the former and ConQuest (Wu, Adams and Wilson, 1998) for the latter. It also offers answers to the practical questions of whether a common set of assessment criteria can, in an academic context such as this one, be meaningfully applied to all subgroups within the candidature and whether analytic criteria are more susceptible to biased ratings than holistic ones. Implications for test fairness and test validity are discussed.     

Theoretical analysis of annealing behaviour of mixed distributions of dislocation loops,voids, and gas bubbles: comparison with annealing behaviour of irradiated reactor component

Abstract

A theoretical analysis of the annealing behaviour of irradiation damage in the form of mixed distributions of dislocation loops, voids, and bubbles is presented. Two limiting cases are considered. The first is where no external vacancy sources and sinks exist, such that vacancies are conserved during the annealing process and the second is where such sources and sinks do exist. Numerical examples are given and comparisons are made with the annealing behaviour of an irradiated reactor component. The influence of an applied stress on the annealing behaviour is evaluated.

MST/1592     

An explorative study of the relationship between lifestyle and driving behaviour among young drivers

The high accident risk among young drivers is a well-known and well-documented fact in most countries, including Denmark. Lifestyle has proven to be related to driving behaviour as well as accident risk among young drivers. However, the underlying process through which the relationship between the lifestyle and the driving behaviour is established is not yet fully understood. Using focus group interviews divided by sex and education this study explores the psychosocial function of driving as well as the process through which a relationship between lifestyle and driving behaviour is established. Twenty-nine young drivers living in the Copenhagen area participated in the study. Data were analysed using a modified version of the Editing Analysis Style.     

A further exploration of sensation seeking propensity,reward sensitivity,depression, anxiety,and the risky behaviour of young novice drivers in a structural equation model

Young novice drivers constitute a major public health concern due to the number of crashes in which they are involved, and the resultant injuries and fatalities. Previous research suggests psychological traits (reward sensitivity, sensation seeking propensity), and psychological states (anxiety, depression) influence their risky behaviour. The relationships between gender, anxiety, depression, reward sensitivity, sensation seeking propensity and risky driving are explored. Participants (390 intermediate drivers, 17–25 years) completed two online surveys at a six month interval. Surveys comprised sociodemographics, Brief Sensation Seeking Scale, Kessler's Psychological Distress Scale, an abridged Sensitivity to Reward Questionnaire, and risky driving behaviour was measured by the Behaviour of Young Novice Drivers Scale. Structural equation modelling revealed anxiety, reward sensitivity and sensation seeking propensity predicted risky driving. Gender was a moderator, with only reward sensitivity predicting risky driving for males. Future interventions which consider the role of rewards, sensation seeking, and mental health may contribute to improved road safety for younger and older road users alike.     

Stop, look, listen, and think? What young children really do when crossing the road.

This study sought to provide basic information about children's behaviour in realistic traffic situations. Most literature in this area has focused on children's knowledge about road safety or has assessed their behaviour in simulated traffic environments. However, until more is known about what children actually do in traffic environments, our ability to identify the important elements for inclusion in educational programmes remains limited. Fifty-six children, aged 5-6 years, took part in a 'treasure trail' activity in which they were confronted with two road crossings, one at a T-junction with a moving car and the other between parked cars. Children's performance was videotaped and coded for relevant behaviours such as stopping at the kerb, looking for traffic, direction of gaze, and style of crossing (i.e. walking vs. running). Results revealed that performance was extremely poor. Sixty percent of the children failed to stop before proceeding from the kerb onto the road. Looking for oncoming traffic was exhibited by no more than 41% of the sample, dropping to as low as 7% in some instances. When looking did occur, it was initially as likely to be in the inappropriate direction (i.e. to the left) as in the appropriate direction (i.e. to the right). Consideration of individual performance revealed the existence of individual differences within the sample; such differences were relatively stable across the two road crossings. These findings, based on controlled naturalistic tasks and detailed observational methods, build on earlier studies that are generally able to provide only estimated rates of children's behaviour.     

Micro-mechanisms, mechanical behaviour and probabilistic fracture analysis of PA 66 fibres

The micro/macro structural evolution of polyamide 66 fibres during tensile loading and failure initiation have been studied by coupling multi-scale measurements such as wide angle X-ray diffraction (WAXD) with profile fitting, birefringence, differential scanning calorimetry (DSC), micro-Raman spectroscopy and mechanical testing at two strain rates. A large dependence of mechanical properties, including strain rate effects, on the behaviour of both oriented and random amorphous regions has been shown with important contributions from the isotropic amorphous domains. The results indicate the presence of compressive residual stresses beneath the skin, showing a skin/core sub-structure. Statistical fracture treatments have been applied using a time-dependent weakest link Weibull model, in order to give an evaluation of the dispersion of defects. Local damage was taken into account using a crack growth propagation law as a function of stress intensity factor near the defect. The paper shows how both experimental and theoretical fracture toughness results are in quite good agreement.     

Multilevel analysis of academic publishing across disciplines: research preference,collaboration, and time on research

This study developed a multilevel model of academic publishing and tested the effects of several predictors on faculty publishing. In particular, the analysis paid special attention to faculty preference, time on research, research collaboration, and faculty discipline. The data we used for this study is the Changing Academic Professions (CAP) data which is the follow-up study of the Carnegie Foundation in 1992. The study found that faculty preference for research affects research publishing. In addition, faculty collaboration with international peers is a critical factor in academic publishing. While time spent on research is related to publishing, time spent on teaching does not have a conflicting effect on faculty research. In the institution level analysis, institutional goal-orientation and institutional mission were found to have effects on academic publishing. However, the principal determinants of academic publishing were found to lie at the individual faculty member level. For each of these findings, there are subtle differences by academic discipline.     

Comparing factor analysis and the Rasch model for ordered response categories: an investigation of the scale of gambling choices

Using both factor analysis (Spearman, 1904) and the Rasch model for ordered response categories (Andrich, 1978), the present study investigated the structure of the Scale of Gambling Choices (SGC, Baron, Dickerson and Blaszczynski, 1995). The scale was administered to a participant sample (n = 210) consisting of 57 first year psychology students, 104 in situ club Electronic Gaming Machine (EGM) players and 49 self-referred problem gamblers. It was hypothesised that the results yielded by factor analysis and Andrich's model would not agree with respect to the behaviour of individual items. This hypothesis was supported; supporting the results of previous research (Johnson, et al., 1995; Raju, et al., 2002; Reise, et al., 1993). It was also hypothesised that a relationship would exist between item factor loadings and item expected value curve slope coefficients. This hypothesis was not supported and so hence did not support the findings of Parsons and Hulin (1982) and Roskam (1985). It was concluded that this was perhaps due to the different latent variable conceptions which exist between the Rasch models and factor analysis (Bollen, 2002). The limitations of the research were outlined and suggestions for future research were made.     

X-ray analysis and ice nucleating behaviour of the Agl-Cul-Kl system

Lattice parameter calculations and ice nucleation studies for the Agl-Cul-Kl system are reported. Using the vacuum fusion method, samples of different compositions were prepared. The formation of cubic solid solution for these samples was confirmed by X-ray diffractograms. It was found that the solid solution of Agl, Cul and Kl having the mol % composition of 602020 has the highest nucleation temperature, –1.70° C, far greater than the nucleating temperature of pure Agl, Cul and Kl.     

Altmetrics analysis of highly cited academic papers in the field of library and information science

Scientometrics - In this study, altmetrics for LIS research papers, and whether OA affects the altmetrics, were analyzed. In addition, by analyzing the differences in the altmetrics in 10 major...     

Comparative performance analysis of versions of TCP in a local network with a mobile radio link

The scenario is that a bulk data transfer is being performed over a TCP connection, from a host on a local area network (LAN) to a mobile host attached to the LAN by a radio link. In an earlier work we had assumed that packet losses in a TCP connection over a radio link are statistically independent. In this paper, we extend this analysis to a Rayleigh fading link, which we model by a two-state Markov model. The bulk throughputs of TCP-OldTahoe and TCP-Tahoe are compared with and without fading, for various average signal-to-noise ratios. We also study the performance with a link protocol on the wireless link, and study the effect of varying the link packet size, the number of link packet attempts, and the vehicle speed. For the parameters of the BSD UNIX implementation, over a 1.5 Mbps wireless link, we find that, with fading, a signal-to-noise ratio of at least 30 dB is required to get reasonable throughput with TCP Tahoe or OldTahoe; this corresponds to at least 100 times more power than is needed without fading. For fixed signal-to-noise ratio, as the vehicle speed varies there are roughly 3 regions of performance: at very low speeds (pedestrian speeds) the throughput is very good; at low vehicular speeds the throughput deteriorates, and again becomes very good at higher vehicle speeds. The speeds corresponding to the various regions depend on the parameters of the link protocol. This work was done while the first author was on Sabbatical at WINLAB, Rutgers University     

Formalizing dimension and response violations of local independence in the unidimensional Rasch model

Local independence in the Rasch model can be violated in two generic ways that are generally not distinguished clearly in the literature. In this paper we distinguish between a violation of unidimensionality, which we call trait dependence, and a specific violation of statistical independence, which we call response dependence, both of which violate local independence. Distinct algebraic formulations for trait and response dependence are developed as violations of the dichotomous Rasch model, data are simulated with varying degrees of dependence according to these formulations, and then analysed according to the Rasch model assuming no violations. Relative to the case of no violation it is shown that trait and response dependence result in opposite effects on the unit of scale as manifested in the range and standard deviation of the scale and the standard deviation of person locations. In the case of trait dependence the scale is reduced; in the case of response dependence it is increased. Again, relative to the case of no violation, the two violations also have opposite effects on the person separation index (analogous to Cronbach's alpha reliability index of traditional test theory in value and construction): it decreases for data with trait dependence; it increases for data with response dependence. A standard way of accounting for dependence is to combine the dependent items into a higher-order polytomous item. This typically results in a decreased person separation index index and Cronbach's alpha, compared with analysing items as discrete, independent items. This occurs irrespective of the kind of dependence in the data, and so further contributes to the two violations not being distinguished clearly. In an attempt to begin to distinguish between them statistically this paper articulates the opposite effects of these two violations in the dichotomous Rasch model.     

Measuring teaching ability with the Rasch model by scaling a series of product and performance tasks

Rasch measurement can provide a much needed solution to scaling teacher ability. Typically, decisions about teacher ability are based on dichotomously scored certification tests focused on knowledge of content or pedagogy. This paper presents early developmental work of a partial-credit teacher-ability scale of 42 tasks (performances and products) with 348 rated items or criteria. The tasks and criteria are aligned with national and state standards for expected teacher knowledge and skills. These tasks are being used in about two-thirds of Florida school districts and are spreading to colleges of education. Over time there will be many variations in both tasks and criteria, but here we focus on the initial system and the Rasch model as part of the plan for development of the system.     

Boundary element analysis of the thermal behaviour in thin-coated cutting tools

Temperature measurement and prediction have been a major focus of machining for several decades, but now these problems become more complex due to the wider use of advanced cutting tool coatings. In all literature items cited the boundary element method (BEM) were used to find the distribution of temperature inside the uncoated tool body or along the tool–chip interface in the machining processes. The BEM-based approach proposed in this paper overcomes this limit and the temperature distribution in thin coated layers is well studied. In this study, a general strategy based on a nonlinear transformation technique is introduced and applied to evaluate the nearly singular integrals occurring in two dimensional (2D) thin-coated structures. For the test problems studied, very promising results are obtained when the thickness to length ratio is in the orders of 1.0E?6 to 1.0E?10, which is sufficient for modeling most thin-coated structures in the micro- or nano-sclaes.