Predictability and skill of boreal winter forecasts made with the ECMWF Seasonal Forecasting System II

The performance of boreal winter forecasts made with the European Centre for Medium-Range Weather Forecasts (ECMWF) System 11 Seasonal Forecasting System is investigated through analyses of ensemble hindcasts for the period 1987-2001. The predictability, or signal-to-noise ratio, associated with the forecasts, and the forecast skill are examined. On average, forecasts of 500 hPa geopotential height (GPH) have skill in most of the Tropics and in a few regions of the extratropics. There is broad, but not perfect, agreement between regions of high predictability and regions of high skill. However, model errors are also identified, in particular regions where the forecast ensemble spread appears too small. For individual winters the information provided by t-values, a simple measure of the forecast signal-to-noise ratio, is investigated. For 2 m surface air temperature (T2m), highest t-values are found in the Tropics but there is considerable interannual variability, and in the tropical Atlantic and Indian basins this variability is not directly tied to the El Nino Southern Oscillation. For GPH there is also large interannual variability in t-values, but these variations cannot easily be predicted from the strength of the tropical sea-surface-temperature anomalies. It is argued that the t-values for 500 hPa GPH can give valuable insight into the oceanic forcing of the atmosphere that generates predictable signals in the model. Consequently, t-values may be a useful tool for understanding, at a mechanistic level, forecast successes and failures. Lastly, the extent to which t-values are useful as a predictor of forecast skill is investigated. For T2m, t-values provide a useful predictor of forecast skill in both the Tropics and extratropics. Except in the equatorial east Pacific, most of the information in t-values is associated with interannual variability of the ensemble-mean forecast rather than interannual variability of the ensemble spread. For GPH, however, t-values provide a useful predictor of forecast skill only in the tropical Pacific region.

The gender gap in real estate sales: negotiation skill or agent selection?

This study examines differences in net selling price for residential real estate across male and female agents. A sample of 2,020 home sales transactions from Fulton County, Georgia are analyzed in a two-stage least squares, geospatial autoregressive corrected, semi-log hedonic model to test for gender and gender selection effects. Although agent gender seems to play a role in naïve models, its role becomes inconclusive as variables controlling for possible price and time on market expectations of the buyers and sellers are introduced to the models. Clear differences in real estate sales prices, time on market, and agent incomes across genders are unlikely due to differences in negotiation performance between genders or the mix of genders in a two-agent negotiation. The evidence suggests an interesting alternative to agent performance: that buyers and sellers with different reservation price and time on market expectations, such as those selling foreclosure homes, tend to select agents along gender lines.

Haptics in medicine and clinical skill acquisition

THE clinical skills of medical professionals rely strongly on the sense of touch, combined with anatomical and diagnostic knowledge. Haptic exploratory procedures allow the expert to detect anomalies via gross and fine palpation, squeezing, and contour following. Haptic feedback is also key to medical interventions, for example when an anaesthetist inserts an epidural needle, a surgeon makes an incision, a dental surgeon drills into a carious lesion, or a veterinarian sutures a wound. Yet, current trends in medical technology and training methods involve less haptic feedback to clinicians and trainees. For example, minimally invasive surgery removes the direct contact between the patient and clinician that gives rise to natural haptic feedback, and furthermore introduces scaling and rotational transforms that confuse the relationship between movements of the hand and the surgical site. Similarly, it is thought that computer-based medical simulation and training systems require high-resolution and realistic haptic feedback to the trainee for significant training transfer to occur. The science and technology of haptics thus has great potential to affect the performance of medical procedures and learning of clinical skills. This special section is about understanding

Self-ratings and observer-ratings of social skill: a manipulation of state social anxiety in anxious and non-anxious children

The role of state and trait anxiety on observer ratings of social skill and negatively biased self-perception of social skill was examined. Participants were aged between 7 and 13 years (mean=9.65; sd=1.77; N=102), 47 had a current anxiety diagnosis and 55 were non-anxious controls. Participants were randomly allocated to a high or low anxiety condition and asked to complete social tasks. Task instructions were adjusted across conditions to manipulate participants’ state anxiety. Observers rated anxious participants as having poorer social skills than non-anxious controls but there was no evidence that anxious participants exhibited a negative self-perception bias, relative to controls. However, as participants’ ratings of state anxiety increased, their perception of their performance became more negatively biased. The results suggest that anxious children may exhibit real impairments in social skill and that high levels of state anxiety can lead to biased judgements of social skills in anxious and non-anxious children.

Amount of mental practice and performance of a simple motor task

The effects of different amounts of mental practice on the performance of a motor skill were studied. Research supports the effectiveness of mental practice on performance; however, little is known about how much practice is needed and whether there is an optimal amount for these practice effects. Participants, 209 students ages 18 to 44 years (M = 20.5, SD = 2.9), completed a pre- and posttest of dart throwing with the nonpreferred hand. In the practice phase, participants completed either 25 (Mental Practice 25), 50 (Mental Practice 50), or 100 (Mental Practice 100) trials of the darts task or 50 trials of a catching task (Catching Task). Performance for all groups improved from pre- to posttest. Improvements for the three mental practice groups were greater than for the Catching Task group; however, there were no differences for the three Mental Practice groups. The findings support the positive effect of mental practice over a control condition and suggest that small amounts of mental practice may be sufficient for performance improvements, at least for a simple motor skill.

Situational and dispositional indicators of performance : competing models in education

The attainment of high grades on the Victorian Certificate of Education (VCE) is critical to the future study and employment prospects of many Australian adolescents. Thus it is important to understand the factors that contribute to performance in the VCE. The aims of this study were twofold: the main aim was to test competing models of academic performance, subsuming a range of situational and dispositional variables based on a) self-efficacy theory, b) target and purpose goals, c) cognitive skills and self-regulatory strategies, and d) positive psychology. These models were each tested in terms of English performance and mathematics performance as these units contribute proportionally the most to overall VCE scores. In order to study whether pressures peculiar to the VCE impact on performance, the competing models were tested in a sample of Victorian students prior to the VCE (year 10) and then during the VCE (year 11). A preliminary study was conducted in order to develop and test four scales required for use in the major study, using an independent sample of 302 year nine students. The results indicated that these new scales were psychometrically reliable and valid. Three-hundred and seven Australian students participated in the year 10 and 11 study. These students were successively asked to provide their final years 9, 10 and 11 English and mathematics grades at times one, three and five and to complete a series of questionnaires at times two and four. Results of the year 10 study indicated that models based on self-efficacy theory were the best predictors of both English and mathematics performance, with high past grades, high self-efficacy and low anxiety contributing most to performance. While the year 10 self-efficacy models, target goal models, positive psychology models, self-regulatory models and cognitive skill based models were each robust in the sample in year 11, a substantial increase in explained variance was observed from year 10 to year 11 in the purpose goal models. Results indicated that students’ mastery goals and their performance-approach goals became substantially more predictive in the VCE than they were prior to the VCE. This result can be taken to suggest that these students responded in very instrumental ways to the pressures, and importance, of their VCE. An integrated model based on a combination of the variables from the competing models was also tested in the VCE. Results showed that these models were comparable, both in English and mathematics, to the self-efficacy models, but explained less variance than the purpose goal models. Thus in terms of parsimony the integrated models were not preferred. The implications of these results in terms of teaching practices and school counseling practices are discussed. It is recommended that students be encouraged to maintain a positive outlook in relation to their schoolwork and that they be encouraged to set their VCE goals in terms of a combination of self-referenced (mastery) and other-referenced (performance-approach) goals.

An empirical examination of feedback : user control and performance in a hapto-audio-visual training environment

Utilising advanced technologies, such as virtual environments (VEs), is of importance to training and education. The need to develop and effectively apply interactive, immersive 3D VEs continues to grow. As with any emerging technology, user acceptance of new software and hardware devices is often difficult to measure and guidelines to introduce and ensure adequate and correct usage of such technologies are lacking. It is therefore imperative to obtain a solid understanding of the important elements that play a role in effective learning through VEs. In particular, 3D VEs may present unusual and varied interaction and adoption considerations. The major contribution of this study is to investigate a complex set of interrelated factors in the relatively new sphere of VEs for training and education. Although many of the factors appears to be important from past research, researcher have not explicitly studied a comprehensive set of inter-dependant, empirically validated factors in order to understand how VEs aid complex procedural knowledge and motor skill learning. By integrating theory from research on training, human computer interaction (HCI), ergonomics and cognitive psychology, this research proposes and validates a model that contributes to application-specific VE efficacy formation. The findings of this study show visual feedback has a significant effect on performance. For tactile/force feedback and auditory feedback, no significant effect were found. For satisfaction, user control is salient for performance. Other factors such as interactivity and system comfort, as well as level of task difficulty, also showed effects on performance.

Retroactive interference and mental practice effects on motor performance : a pilot study

This study examined the effect of similar versus dissimilar retroactive interference on the mental practice effects for performing a novel motor skill. Research has shown that mental practice of a motor task can interfere with learning and performance of the task; however, little is known about how different retroactive interference activities affect mental practice effects. 90 volunteers ages 18 to 51 years (M=26.8, SD=9.6) completed a pre-test and post-test of 10 sets of five trials of a throwing task with the non-preferred hand. In the practice phase, participants mentally practiced the throwing task and then mentally practiced a task that was similar, dissimilar, or completed an unrelated reading task. Performance for all groups improved from pre- to post-test; however, there were no differences in increases for the three groups. The findings suggest that mental practice of similar and dissimilar tasks produced no significant interference in performance.

Process in skill acquisition : motivation, interruptions, memory, affective states, and metacognition

Models of skill acquisition, such as Ackerman's (1988) theory of skill acquisition, largely ignore the experiences and dynamic internal processes of a person while learning a skill (e.g., how they feel, what strategies they are using, the role of the external environment). Riding and Powell (1993) suggested that the information-processing model (a common conceptualisation of learning and thinking) is an inadequate model to explain the complexities of human brain functions. These models are largely holistic, and do not provide detail about the qualitative aspects of a person's learning experience. This paper attempts to highlight the importance of a dynamic description of skill acquisition and to “unpack” the skill acquisition stages, with a focus given to process rather than performance or outcome. Learning more about what is going on “inside people's heads” whilst learning a skill, and what feelings or affective states are present, can inform both skill acquisition theory and various practical issues, such as why some training programs fail and some succeed. The role of emotions, motivation, environment, and other factors; the concepts of skill and ability; and various theories of skill acquisition are discussed. This highlights missing elements in the typical cognitive experimental focus. The concept of process itself is explored, with a focus on learning in general. Process-oriented factors such as motivation, memory, interruptions, emotion, and metacognition are investigated in relation to skilled performance. Areas for future research and some practical implications for training are outlined.

Online motor control in children with developmental coordination disorder: chronometric analysis of double-step reaching performance

Background
Although there are a number of plausible accounts to explain movement clumsiness in children [or developmental coordination disorder (DCD)], the cause(s) of the disorder remain(s) an issue of debate. One aspect of motor control that is particularly important to the fluid expression of skill is rapid online control (ROC). Data on DCD have been conflicting. While some recent work using double-step reaching suggests no difficulty in online control, others suggest deficits (e.g. based on sequential pointing). To help resolve this debate, we suggest two things: use of recent neuro-computational models as a framework for investigating motor control in DCD, and more rigorous investigation of double-step reaching. Our working assumption here is that ROC is only viable through the seamless integration of predictive (or forward) models of movement and feedback-based mechanisms.

Aim
The aim of this chronometric study was to explore ROC in children with DCD using a double-step reaching paradigm. We predicted slower online adjustments in DCD based on the argument that these children manifest a core difficulty in predictive control.

Methods
Participants were a group of 17 children with DCD and 27 typically developing children aged between 7 and 12 years. Visual targets were presented on a 17-inch LCD touch screen, inclined to an angle of 15° from horizontal. The children were instructed to press each target as it appeared as quickly and accurately as possible. For 80% of the trials, the central target location remained unchanged for the duration of the movement (non-jump trials), while for the remaining 20% of trials, the target jumped at movement onset to one of the two peripheral locations (jump trials). Reaction time (RT), movement time (MT) and reaching errors were recorded.

Results
For both groups, RT did not vary according to trial condition, while children with DCD were slower to initiate movement. Further, the MT of children with DCD was prolonged to a far greater extent on jump trials relative to controls, with a large effect size. As well, children with DCD committed significantly more errors, notably a reduced ability to inhibit central responses on jump trials.

Conclusion
Our findings help reconcile some disparate findings in the literature using similar tasks. The pattern of performance in children with DCD suggests impairment in the ability to make rapid online adjustments that are based on a predictive (or internal) model of the action. These results pave the way for future kinematic investigation.

Development and validation of the Approach-Iron Skill Test for use in golf

The primary aim of this study was to develop and validate a golf-specific approach-iron test for use with elite and high-level amateur golfers. Elite (n=26) and high-level amateur (n=23) golfers were recruited for this study. The ‘Approach-Iron Skill Test’ requires players to hit a total of 27 shots. Specifically, three shots are hit at each of nine targets on a specially constructed driving range in a randomised order. A real-time launch monitor positioned behind the player, measured the carry distance for each of these shots. A scoring system was developed based on the percentage error index of each shot, meaning that 81 points was the maximum score possible (with a maximum of three points per shot). Two rounds of the test were performed. For both rounds of the test, elite-level golfers scored significantly higher than their high-level amateur counterparts (56.3±5.6 and 58.5±4.6 points versus 46.0±6.3 and 46.1±6.7 points, respectively) (P<0.05). For both elite and high-level players, 95% limits of agreement statistics also indicated that the test showed good test–retest reliability (2.1±7.9 and 0.2±10.8, respectively). Due to the clinimetric properties of the test, we conclude that the Approach-Iron Skill Test is suitable for further examination with the players examined in this study.

The expectation-performance gap in generic skills in accounting graduates : Evidence from Sri Lanka

Purpose
The purpose of this paper is to investigate the generic skills that are important for the career success of accounting graduates in Sri Lanka from the perspectives of university educators and employers.

Design/methodology/approach
Bui and Porter's (2010) expectation-performance gap framework was modified to match with the context of the current study. Data collected via questionnaire survey was analysed for non-parametric tests: the Wilcoxon signed-rank test and the Mann-Whitney test, using SPSS version 20, and quantified the expectation-performance gap and its components.

Findings
The major finding of this research is that the main cause for the expectation-performance gap, as identified in the analysis of the constraint gap is university educators’ low confidence in teaching the required generic skills for career success of graduates. However, university educators are aware of the employer expectations of graduate accountants in terms of generic skills. Employers indicated that many of the generic skills are not achieved by the accounting graduates.

Practical implications
Findings of this study reflect the importance of expanding the accounting curricula by embedding and assessing generic skill development activities. In addition, it is vital to develop the capacities of university educators in terms of teaching and assessing generic skills in accounting degree programmes.

Originality/value
This study contributes to the literature as one of few studies that investigate the generic skills development of accounting graduates in Asia, particularly in Sri Lanka.

Development and measurement properties of a putting skill test for high-level golf

Despite a recent increase in the amount of research investigating performance in golf, a comprehensive putting skill test has not been reported in the peer-reviewed literature. In this study, the Golf Australia Putting Test (GAPT) was developed and a series of measurement properties were assessed. Elite (n = 18) and high-level amateur (HLA; n = 22) participants completed six single putts from various areas on six concentric circles (circle radii = 0.9, 1.5, 3.0, 4.6, 6.1 and 7.6 m). Using a scoring system that rewarded participants for holing putts from longer distances, the maximum score from a single round of the test (i.e. 36 putts) was 27 points. After two rounds of the test were completed by all players, a subsample of participants (elite, n = 15; HLA, n = 7) had their putting performance recorded during tournament play for a period of 90 days to assess criterion (predictive) validity of the test. The reliability, sensitivity and discriminative validity of the GAPT were also assessed. Better agreement between Rounds 1 and 2 scores was noted in the elite group, whilst reliability values were similar for both groups. Further, the GAPT scores were shown to predict players from the elite and high-ability groups with a low classification error. An equation for predicting on-course performance from GAPT scores was also developed. Findings from this study indicate that the GAPT is a valid and reliable tool for high-level players and the GAPT may be used for player evaluation in the field.