The List of Social Situation Problems: Reliability and validity in an adolescent Spanish-speaking sample

The aim of this study was to analyze the psychometric properties of the Spanish translation of the List of Social Situation Problems (LSSP; S. H. Spence, 1980). The questionnaire was administered to a sample of 388 adolescents between the ages of 12 and 18. Exploratory factor analysis identified four factors: Social Anxiety, Adult Oppositional, Assertiveness, and Making Friends, which accounted for 26.64% of the variance. Internal consistency of the total scale was high (alpha = .86). Correlations between the LSSP and two self-report measures of social anxiety, the Questionnaire about Interpersonal Difficulties for Adolescents (r = .45) and the Social Phobia and Anxiety Inventory (r = .48), were statistically significant. A significant difference was found between LSSP total scores for adolescents with and without social anxiety (d = 1.14), supporting the construct validity of the scale.

Comparability of perceptual analysis of speech characteristics in Australian and Swedish speakers with multiple sclerosis

The aims of the present study were to compare the perceptual assessments of deviant speech signs (dysarthria) exhibited by Australian and Swedish speakers with multiple sclerosis (MS) and to explore whether judgements of dysarthria differed depending on whether the speakers and the judges spoke the same or different languages. Ten Australian and 10 Swedish individuals with MS (matched as closely as possible for age, gender, progression type and severity of dysarthria) were assessed by 2 Australian and 2 Swedish clinically experienced judges using a protocol including 33 speech parameters. Results show that the following perceptual dimensions were identified by both pairs of judges in both groups of speakers to a just noticeable or moderate degree: imprecise consonants, inappropriate pitch level, reduced general rate, and glottal fry. The reliability (Spearman rank-order correlation) of the consensus ratings from the Australian and the Swedish judges was high, with a mean rho of 85.7 for the Australian speakers and mean rho of 84.3 for the Swedish speakers. The most difficult perceptual parameters to assess (i.e. to agree on) included harshness, level of pitch and loudness, precision of consonants and general stress pattern. The study indicated that perceptual assessments of speech characteristics in individuals with MS are informative and can be achieved with high inter-judge reliability irrespective of the judge's knowledge of the speaker's language. Copyright (C) 2003 S. Karger AG, Basel.

Gray's model of personality and aggregate level factor analysis

Previous research shows that correlations tend to increase in magnitude when individuals are aggregated across groups. This suggests that uncorrelated constellations of personality variables (such as the primary scales of Extraversion and Neuroticism) may display much higher correlations in aggregate factor analysis. We hypothesize and report that individual level factor analysis can be explained in terms of Giant Three (or Big Five) descriptions of personality, whereas aggregate level factor analysis can be explained in terms of Gray's physiological based model. Although alternative interpretations exist, aggregate level factor analysis may correctly identify the basis of an individual's personality as a result of better reliability of measures due to aggregation. We discuss the implications of this form of analysis in terms of construct validity, personality theory, and its applicability in general. Copyright (C) 2003 John Wiley Sons, Ltd.

Reliability of the Knee Examination in Osteoarthritis: Effect of Standardization

Objective. To assess the reliability of physical examination of the osteoarthritic (OA) knee by rheumatologists, and to evaluate the benefits of standardization. Methods. Forty-two physical signs and techniques were evaluated using a 6 X 6 Latin square design. Patients with mild to severe knee OA, based on physical and radiographic signs, were examined in random order prior to and following standardization of techniques. For those signs with dichotomous scales, agreement among the rheumatologists was calculated as the prevalence-adjusted bias-adjusted kappa (PABAK), while for the signs with continuous and ordinal scales, a reliability coefficient (R-c) was calculated using analysis of variance. A PABAK of >0.60 and an Re of >0.80 were considered to indicate adequate reliability. Results. Adequate poststandardization reliability was achieved for 30 of 42 physical signs/techniques (71%). The most highly reliable signs identified by physical examination of the OA knee included alignment by goniometer (R-c = 0.99), bony swelling (R-c = 0.97), general passive crepitus (R-c = 0.96), gait by inspection (PABAK = 0.78), effusion bulge sign (R-c = 0.97), quadriceps atrophy (R. = 0.97), medial tibiofemoral tenderness (R-c = 0.94), lateral tibiofemoral tenderness (R-c = 0.85), patellofemoral tenderness by grind test (R-c = 0.94), and flexion contracture (R-c = 0.95). The standardization process resulted in substantial improvements in reliability for evaluation of a number of physical signs, although for some signs, minimal or no effect of standardization was noted. After standardization, warmth (PABAK = 0.14), medial instability at 30degrees flexion (PABAK = 0.02), and lateral instability at 30degrees flexion (PABAK = 0.34) were the only 3 signs that were highly unreliable. Conclusion. With the exception of physical examinations for instability, a comprehensive knee examination can be performed with adequate reliability. Standardization further improves the reliability for some physical signs and techniques. The application of these findings to future OA studies will contribute to improved outcome assessments in OA.

Confirmatory factor analysis and psychometric properties of the Anxiety Sensitivity Index-Revised in clinical and normative populations

The present investigation aimed to critically examine the factor structure and psychometric properties of the Anxiety Sensitivity Index - Revised (ASI-R). Confirmatory factor analysis using a clinical sample of adults (N = 248) revealed that the ASI-R could be improved substantially through the removal of 15 problematic items in order to account for the most robust dimensions of anxiety sensitivity. This modified scale was renamed the 21-item Anxiety Sensitivity Index (21-item ASI) and reanalyzed with a large sample of normative adults (N = 435), revealing configural and metric invariance across groups. Further comparisons with other alternative models, using multi-sample analysis, indicated the 21-item ASI to be the best fitting model for both groups. There was also evidence of internal consistency, test-retest reliability, and construct validity for both samples suggesting that the 21-item ASI is a useful assessment device for investigating the construct of anxiety sensitivity in both clinical and normative populations.

Reliability and validity of arm volume measurements for assessment of lymphedema

Background and Purpose. Arm lymphedema following breast cancer In this study, we assessed the surgery is a continuing problem. reliability and validity of circumferential measurements and water displacement for measuring upper-limb volume. Subjects. Participants included subjects who had had breast cancer surgery, including axillary dissection-19 with and 22 without a diagnosis of arm lymphedema-and 25 control subjects. Methods. Two raters measured each subject by using circumferential tape measurements at specified distances from the fingertips and in relation to anatornic landmarks and by using water displacement. Interrater reliability was calculated by analysis of variance and multilevel modeling. Volumes from circumferential measurements were compared with those from water displacement by use of means and correlation coefficients, respectively. The standard error of measurement, minimum detectable change (MDC), and limits of agreement (LOA) for volumes also were calculated. Results. Arm volumes obtained with these methods had high reliability. Compared with volumes from water displacement, volumes from circumferential measurements had high validity, although these volumes were slightly larger. Expected differences between subjects with and without clinical lymphedema following breast cancer were found. The MDC of volumes or the error associated with a single measure for data based oil anatomic landmarks was lower than that based oil distance from fingertips. The mean LOA with water displacement were lower for data based on anatomic landmarks than for data based on distance from fingertips. Discussion and Conclusion. Volumes calculated from anatomic landmarks are reliable, valid, and more accurate than those obtained from circumferential measurements based on distance from fingertips.

Use of latent profile analysis to identify eating disorder phenotypes in an adult Australian twin cohort

Context: The relationships among the different eating disorders that exist in the community are poorly understood, especially for residual disorders in which bingeing or purging occurs in the absence of other behaviors. Objective: To examine a community sample for the number of mutually exclusive weight and eating profiles. Design: Data regarding lifetime eating disorder symptoms and weight range were submitted to a latent profile analysis. Profiles were compared regarding personality, current eating and weight, retrospectively reported life events, and lifetime depressive psychopathology. Setting: Longitudinal study among female twins from the Australian Twin Registry in whom eating was assessed by a telephone interview. Participants: A community sample of 1002 twins (individuals) who had participated in earlier waves of data collection. Main Outcome Measures: Number and clinical character of latent profiles. Results: The best fit was a 5-profile solution with women who were (1) of normal weight with few lifetime eating disorders (4.3%), (2) overweight (10.6% had a lifetime eating disorder), (3) underweight and generally had no eating disorders except for 5.3% who had restricting anorexia nervosa, (4) of low to normal weight (89.0% had a lifetime eating disorder), and (5) obese (37.0% had a lifetime eating disorder). Each profile contained more than 1 type of lifetime eating disorder except for the third profile. Women in the first and third profiles had the best functioning, with women in the fourth and fifth profiles having similarly poorer functioning. The women in the fourth group had a symptom profile distinctive from the other 4 groups in terms of severity; they were also more likely to have had lifetime major depression and suicidality. Conclusion: Lifetime weight ranges and the severity of eating disorder symptoms affected clustering more than the type of eating disorder symptom.

Formal analysis of human-computer interaction using model checking

Experiments with simulators allow psychologists to better understand the causes of human errors and build models of cognitive processes to be used in human reliability assessment (HRA). This paper investigates an approach to task failure analysis based on patterns of behaviour, by contrast to more traditional event-based approaches. It considers, as a case study, a formal model of an air traffic control (ATC) system which incorporates controller behaviour. The cognitive model is formalised in the CSP process algebra. Patterns of behaviour are expressed as temporal logic properties. Then a model-checking technique is used to verify whether the decomposition of the operator's behaviour into patterns is sound and complete with respect to the cognitive model. The decomposition is shown to be incomplete and a new behavioural pattern is identified, which appears to have been overlooked in the analysis of the data provided by the experiments with the simulator. This illustrates how formal analysis of operator models can yield fresh insights into how failures may arise in interactive systems.

Analysis of common attacks in public-key cryptosystems based on low-density parity-check codes

The security and reliability of a class of public-key cryptosystems against attacks by unauthorized parties, who had acquired partial knowledge of one or more of the private key components and/or of the message, were discussed. The standard statistical mechanical methods of dealing with diluted spin systems with replica symmetric considerations were analyzed. The dynamical transition which defined decryption success in practical situation was studied. The phase diagrams which showed the dynamical threshold as a function of the partial acquired knowledge of the private key were also presented.

Using QFD for e-business planning and analysis in a micro-sized enterprise

Purpose - The purpose of this paper is to show how QFD can be used as part of a structured planning and analysis framework for micro-sized enterprises to build-up their e-business capabilities. Design/methodology/approach - This case study has been produced using a new framework which integrates the balanced scorecard, value chain and quality function deployment techniques into an integrated framework known as the E-Business Planning and Analysis Framework (E-PAF). It has been produced using an action research approach. Findings - A new framework with a supporting case study is provided. This case study has demonstrated that the framework can be applied successfully to micro-sized enterprises (those with less than ten employees) to successfully plan new strategic and technical developments. This will enhance the online service that the company is able to provide. Research limitations/implications - This paper presents a single case study. The technical recommendations are currently being implemented. Originality/value - Such analytical techniques are most commonly associated with large organisations, and are not specifically associated with e-business planning. This paper provides a new framework that will be of general applicability to other similarly sized enterprises that are looking to improve e-business capabilities. © Emerald Group Publishing Limited.

Reliability:its implications in production systems design

Research on production systems design has in recent years tended to concentrate on ‘software’ factors such as organisational aspects, work design, and the planning of the production operations. In contrast, relatively little attention has been paid to maximising the contributions made by fixed assets, particularly machines and equipment. However, as the cost of unproductive machine time has increased, reliability, particularly of machine tools, has become ever more important. Reliability theory and research has traditionally been based in the main on electrical and electronic equipment whereas mechanical devices, especially machine tools, have not received sufficiently objective treatment. A recently completed research project has considered the reliability of machine tools by taking sample surveys of purchasers, maintainers and manufacturers. Breakdown data were also collected from a number of engineering companies and analysed using both manual and computer techniques. Results obtained have provided an indication of those factors most likely to influence reliability and which in turn could lead to improved design and selection of machine tool systems. Statistical analysis of long-term field data has revealed patterns of trends of failure which could help in the design of more meaningful maintenance schemes.

Data analysis methods in optometry. Part 5: correlation

1. Pearson's correlation coefficient only tests whether the data fit a linear model. With large numbers of observations, quite small values of r become significant and the X variable may only account for a minute proportion of the variance in Y. Hence, the value of r squared should always be calculated and included in a discussion of the significance of r. 2. The use of r assumes that a bivariate normal distribution is present and this assumption should be examined prior to the study. If Pearson's r is not appropriate, then a non-parametric correlation coefficient such as Spearman's rs may be used. 3. A significant correlation should not be interpreted as indicating causation especially in observational studies in which there is a high probability that the two variables are correlated because of their mutual correlations with other variables. 4. In studies of measurement error, there are problems in using r as a test of reliability and the ‘intra-class correlation coefficient’ should be used as an alternative. A correlation test provides only limited information as to the relationship between two variables. Fitting a regression line to the data using the method known as ‘least square’ provides much more information and the methods of regression and their application in optometry will be discussed in the next article.