Showing papers on "Reliability (statistics) published in 2001"
TL;DR: The PedsQL distinguished between healthy children and pediatric patients with acute or chronic health conditions, was related to indicators of morbidity and illness burden, and displayed a factor-derived solution largely consistent with the a priori conceptually-derived scales.
Abstract: Background.The PedsQL (Pediatric Quality of Life Inventory) (Children’s Hospital and Health Center, San Diego, California) is a modular instrument for measuring health-related quality of life (HRQOL) in children and adolescents ages 2 to 18. The PedsQL 4.0 Generic Core Scales are multidimensional ch
4,155 citations
University of Rochester1, Harvard University2, Johns Hopkins University3, Boston University4, Emory University5, Rutgers University6, University of Kansas7, Rush University Medical Center8, Columbia University9, University of California, San Diego10, University of Michigan11, Wake Forest University12
TL;DR: The limited longitudinal database indicates that the UHDRS may be useful for tracking changes in the clinical features of HD over time and there was an excellent degree of interrater reliability for the motor scores.
Abstract: The Unified Huntington's disease Rating Scale (UHDRS) was developed as a clinical rating scale to assess four domains of clinical performance and capacity in HD: motor function, cognitive function, behavioral abnormalities, and functional capacity. We assessed the internal consistency and the intercorrelations for the four domains and examined changes in ratings over time. We also performed an interrater reliability study of the motor assessment. We found there was a high degree of internal consistency within each of the domains of the UHDRS and that there were significant intercorrelations between the domains of the UHDRS, with the exception of the total behavioral score. There was an excellent degree of interrater reliability for the motor scores. Our limited longitudinal database indicates that the UHDRS may be useful for tracking changes in the clinical features of HD over time. The UHDRS assesses relevant clinical features of HD and appears to be appropriate for repeated administration during clinical studies.
1,786 citations
TL;DR: In this paper, the industrial application of motor current signature analysis (MCSA) to diagnose faults in three-phase induction motor drives is discussed, which is a noninvasive, online monitoring technique for the diagnosis of problems in induction motors.
Abstract: Three-phase induction motors are the "workhorses" of industry and are the most widely used electrical machines. In an industrialized nation, they can typically consume between 40 to 50% of all the generated capacity of that country. This article focuses on the industrial application of motor current signature analysis (MCSA) to diagnose faults in three-phase induction motor drives. MCSA is a noninvasive, online monitoring technique for the diagnosis of problems in induction motors. Reliability-based maintenance (RBM) and condition-based maintenance (CBM) strategies are now widely used by industry, and health monitoring of electrical drives is a major feature in such programs.
1,054 citations
TL;DR: The most reliable measures of power and the factors affecting reliability are identified to help exercise practitioners and researchers select or design good measures and protocols for tests of physical performance.
Abstract: The reliability of power in tests of physical performance affects the precision of assessment of athletes, patients, clients and study participants. In this meta-analytic review we identify the most reliable measures of power and the factors affecting reliability. Our measures of reliability were the typical (standard) error of measurement expressed as a coefficient of variation (CV) and the percent change in the mean between trials. We meta-analysed these measures for power or work from 101 studies of healthy adults. Measures and tests with the smallest CV in exercise of a given duration include field tests of sprint running (∼0.9%), peak power in an incremental test on a treadmill or cycle ergometer (∼0.9%), equivalent mean power in a constant-power test lasting 1 minute to 3 hours on a treadmill or cycle ergometer (0.9 to 2.0%), lactate-threshold power (∼1.5%), and jump height or distance (∼2.0%). The CV for mean power on isokinetic ergometers was relatively large (>4%). CV were larger for nonathletes versus athletes (1.3 ×), female versus male nonathletes (1.4 ×), shorter (∼1-second) and longer (∼1-hour) versus 1-minute tests (≤1.6 ×), and respiratory- versus ergometer-based measures of power (1.4 to 1.6 ×). There was no clear-cut effect of time between trials. The importance of a practice trial was evident in studies with >2 trials: the CV between the first 2 trials was 1.3 times the CV between subsequent trials; performance also improved by 1.2% between the first 2 trials but by only 0.2% between subsequent trials. These findings should help exercise practitioners and researchers select or design good measures and protocols for tests of physical performance.
755 citations
TL;DR: Theory and methods of structural reliability are briefly summarized and reviewed, both in original and standard space Some extreme examples demonstrate where and why these methods do not work Importance sampling schemes for updating approximate probability estimates are described Algorithmic problems are addressed Some new fields of potential application are outlined Most urgent is the development of suitable optimization procedures for structures as discussed by the authors.
715 citations
TL;DR: In this article, the authors revisited several conceptual and methodological issues inherent, but often overlooked, in using the importance-performance analysis framework in hotel and tourism research. And they provided suggestions for future tourism and hospitality research applying importanceperformance analysis, which has gained popularity among hospitality and tourism researchers for its simplicity and ease of application.
668 citations
Journal Article•
TL;DR: Most questions on the core BRFSS instrument were at least moderately reliable and valid, and many were highly reliable and invalid, and additional research is needed for some measures.
Abstract: Objectives To assess the reliability and validity of measures on the BRFSS, to assist users in evaluating the quality of BRFSS data, and to identify areas for further research Methods Review and summary of reliability and validity studies of measures on the BRFSS and studies of measures that were the same or similar to those on the BRFSS from other surveys Results Measures determined to be of high reliability and high validity were current smoker, blood pressure screening, height, weight, and BMI, and several demographic characteristics Measures of both moderate reliability and validity included when last mammography was received, clinical breast exam, sedentary lifestyle, intense leisure-time physical activity, and fruit and vegetable consumption Few measures were of low validity and only one measure was determined to be of low reliability Several other measures were of high or moderate reliability or validity, but not both The reliability or validity could not be determined for some measures, primarily due to lack of research Conclusions Most questions on the core BRFSS instrument were at least moderately reliable and valid, and many were highly reliable and valid Additional research is needed for some measures
633 citations
TL;DR: An improved heat pulse method, termed the heat ratio method (HRM), is presented, to measure low and reverse rates of sap flow in woody plants, which has several important advantages over the CHPM, including improved measurement range and resolution.
Abstract: The compensation heat pulse method (CHPM) is of limited value for measuring low rates of sap flow in woody plants. Recent application of the CHPM to woody roots has further illustrated some of the constraints of this technique. Here we present an improved heat pulse method, termed the heat ratio method (HRM), to measure low and reverse rates of sap flow in woody plants. The HRM has several important advantages over the CHPM, including improved measurement range and resolution, protocols to correct for physical and thermal errors in sensor deployment, and a simple linear function to describe wound effects. We describe the theory and methodological protocols of the HRM, provide wound correction coefficients, and validate the reliability and accuracy of the technique against gravimetric measurements of transpiration.
598 citations
TL;DR: The WMFT is an instrument with high interrater reliability, internal consistency, test-retest reliability, and adequate stability, and is concluded to be an instrument that is suitable for assessing upper extremity motor function in adults with hemiplegia.
520 citations
TL;DR: In this article, moment methods for structural reliability are investigated and five moment method formulas are presented and investigated, and the accuracy and efficiency of these methods are demonstrated using numerical examples. And the moment methods, being very simple, have no shortcomings with respect to design points, and thus are convenient to be applied to structural reliability analysis.
512 citations
Journal Article•
TL;DR: In this paper, the effect of negative reviews on retailer evaluation and patronage intention was examined and it was shown that the extent of WOM search depends on the consumer's reasons for choosing an online retailer and the influence of negative WOM information on perceived reliability and purchase intentions is determined largely by familiarity with the retailer and differs based on whether the retailer is a pure-Internet or clicks-and-mortar firm.
Abstract: The use of the WWW as a venue for voicing opinions, complaints and recommendations on products and firms has been widely reported in the popular media. However little is known how consumers use these reviews and if they subsequently have any influence on evaluations and purchase intentions of products and retailers. This study examines the effect of negative reviews on retailer evaluation and patronage intention given that the consumer has already made a product/brand decision. Our results indicate that the extent of WOM search depends on the consumer’s reasons for choosing an online retailer. Further the influence of negative WOM information on perceived reliability and purchase intentions is determined largely by familiarity with the retailer and differs based on whether the retailer is a pure-Internet or clicks-and-mortar firm. Managerial implications for positioning strategies to minimize the effect of negative word-ofmouth have been discussed.
TL;DR: In this article, the authors attempted to shed some light on the past, present, and future of life-cycle management of highway bridges, and concluded that additional research is required to develop better life cycle models and tools to quantify the risks, costs, and benefits associated with highway bridges as well as their interrelationships in highway networks.
Abstract: The objective of bridge management is to allocate and use the limited resources to balance lifetime reliability and life-cycle cost in an optimal manner. As the 20th century has drawn to a close, it is appropriate to reflect on the birth and growth of bridge management systems, to examine where they are today, and to predict their future. In this paper, it is attempted to shed some light on the past, present, and future of life-cycle management of highway bridges. It is shown that current bridge management systems have limitations and that these limitations can be overcome by using a reliability-based approach. It is concluded that additional research is required to develop better life-cycle models and tools to quantify the risks, costs, and benefits associated with highway bridges as well as their interrelationships in highway networks.
TL;DR: The reliability studies showed that handgrip and indexgrip strength measured with the Jamar dynamometer is a reliable method and can be recommended for use in clinical practice, and sex is a more important determinant of hand strength than age, height and body weight.
Abstract: The intra- and inter-tester reliability for measurement of handgrip strength and indexgrip strength using the Jamar dynamometer was investigated in 32 healthy volunteers, and the intra-tester relia ...
TL;DR: In this article, the most frequently used power system maintenance strategies are reviewed and a distinction is made between strategies where maintenance consists of replacement by a new (or "good as new") component and where it is represented by a less costly activity resulting in a limited improvement of the component's condition.
Abstract: In this paper, the most frequently used power system maintenance strategies are reviewed. Distinction is made between strategies where maintenance consists of replacement by a new (or "good as new") component and where it is represented by a less costly activity resulting in a limited improvement of the component's condition. Methods are also divided into categories where maintenance is performed at fixed intervals and where it is carried out as needed. A further distinction is made between heuristic methods and those based on mathematical models; the models themselves can be deterministic or probabilistic. From a review of present maintenance policies in electric utilities, it is concluded that maintenance at fixed intervals is the most frequently used approach, often augmented by additional corrections. Newer "as needed"-type methods, such as reliability-centered maintenance (RCM), are increasingly considered for application in North America, but methods based on mathematical models are hardly ever used or even considered. Yet only mathematical approaches where component deterioration and condition improvement by maintenance are quantitatively linked can determine the effect of maintenance on reliability. Although more complex, probabilistic models have advantages over deterministic ones: they are capable of describing actual processes more realistically, and also facilitate optimization for maximal reliability or minimal costs.
TL;DR: Herb-drug interactions undoubtedly do occur and may put individuals at risk, however the present knowledge is incomplete and more research is urgently needed.
Abstract: Aims
The aim of this systematic review was to assess the published clinical evidence on interactions between herbal and conventional drugs.
TL;DR: In this article, the reliability of visual quality ratings of landscapes, and the validity of photographic representations used when making these ratings are explored, and data from several studies are re-analyzed to demonstrate how professionals should evaluate the reliability and validity of their visual landscape assessments.
TL;DR: This paper examined the reliability of some of the aggregate evidence, and presented an alternative framework for analysing these questions, and suggested that the relationship between changes in average schooling and growth is weak in the cross-country data.
TL;DR: In this article, the authors proposed a methodology to apply Bayesian networks to structural system reliability reassessment, with the incorporation of two important features of large structures: (1) multiple failure sequences, and (2) correlations between component-level limit states.
TL;DR: Comparisons of predicted and observed building damage highlight the limitations of using current deterministic approaches for post-earthquake building condition assessment and the prospects for future improvements in earthquake-resistant design procedures based on a more rational probability-based treatment of uncertainty are examined.
01 Jan 2001
TL;DR: The Functional Rating Index appears to be psychometrically sound with regard to reliability, validity, and responsiveness and is clearly superior to other instruments with regards to clinical utility.
Abstract: ministration). Methods. One hundred thirty-nine subjects with spinal complaints participated in four different cohorts to study reliability, validity, responsiveness, and clinical utility. Results. Reliability: Test-retest: Intraclass correlation coefficient was excellent (ICC3,k 5 0.99); interitem correlation: Item efficiency was good, ranging between 0.54 and 0.82, with a moderate correlation among all items; Cronbach’s alpha was excellent (0.92). Validity: construct: The Functional Rating Index correlated with the Disability Rating Index (0.76), the Short Form-12 Physical Component Score (0.76), and the Short Form-12 Mental Component Score (0.36). Responsiveness: Overall, the size effect was 1.24, which is commendable. Clinical utility: Time required by the patient and staff averaged 78 seconds per administration, which is noteworthy. Effect of Sociodemographics: Total scores were not affected by education, gender, nor age, suggesting minimal external validity bias. Conclusions. The Functional Rating Index appears to be psychometrically sound with regard to reliability, validity, and responsiveness and is clearly superior to other instruments with regard to clinical utility. The Functional Rating Index is a promising useful instrument in the assessment of
TL;DR: In this article, the concept of robust reliability is defined to take into account uncertainties from structural modeling in addition to the uncertain excitement that a structure will experience during its lifetime, and a Bayesian probabilistic methodology for system identification is integrated for updating the assessment of the robust reliability based on dynamic test data.
TL;DR: A simple algorithm is proposed firstly to generate all lower boundary points for d, and then the system reliability can be calculated in terms of such points, and the probability that the maximum flow of the network is not less than d is evaluated.
TL;DR: Based on the expected Fisher information matrix, asymptotic inference procedures for R and other general functions of the parameters are developed and a bootstrap method to estimatevariance for the maximum likelihood estimators is discussed.
Abstract: Inferencefor R=P(Y
TL;DR: It is concluded that future research and development should devote additional attention to the measurement properties of functional assessment instruments, with special attention paid to their validity and reliability.
TL;DR: Findings indicate that the Melbourne Assessment of Unilateral Upper Limb Function is a reliable tool for measuring the quality of unilateral upper-limb movement in children with CP.
Abstract: This study examines the reliability of the Melbourne Assessment of Unilateral Upper Limb Function: a quantitative test of quality of movement in children with neurological impairment. The assessment was administered to 20 children aged from 5 to 16 years (mean age 9 years 10 months, SD 2 years 10 months) who had various types and degrees of cerebral palsy (CP). The performances of the 20 children during assessment were videotaped for subsequent scoring by 15 occupational therapists. Scores were analyzed for internal consistency of test items, inter- and intrarater reliability of scorings of the same videotapes, and test-retest reliability using repeat videotaping. Results revealed very high internal consistency of test items (alpha=0.96), moderate to high agreement both within and between raters for all test items (intraclass correlations of at least 0.7) apart from item 16 (hand to mouth and down), and high interrater reliability (0.95) and intrarater reliability (0.97) for total test scores. Test-retest results revealed moderate to high intrarater reliability for item totals (mean of 0.83 and 0.79) for each rater and high reliability for test totals (0.98 and 0.97). These findings indicate that the Melbourne Assessment of Unilateral Upper Limb Function is a reliable tool for measuring the quality of unilateral upper-limb movement in children with CP.
TL;DR: The development and validation of a novel questionnaire method for assessing behavior and temperament in 1-year-old guide dogs is described and it is suggested that such methods can provide a useful and accurate means of predicting the suitability of dogs for guiding work.
TL;DR: QMT shows greater reliability and is easier to implement than MMT, and will be a superior measure of strength for use in pediatric, neuromuscular, multicenter clinical trials.
Abstract: Measurements of muscle strength in clinical trials of Duchenne muscular dystrophy have relied heavily on manual muscle testing (MMT). The high level of intra- and interrater variability of MMT compromises clinical study results. We compared the reliability of 12 clinical evaluators in performing MMT and quantitative muscle testing (QMT) on 12 children with muscular dystrophy. QMT was reliable, with an interclass correlation coefficient (ICC) of >0.9 for biceps and grip strength, and >0.8 for quadriceps strength. Training of both subjects and evaluators was easily accomplished. MMT was not as reliable, and required repeated training of evaluators to bring all groups to an ICC >0.75 for shoulder abduction, elbow and hip flexion, knee extension, and ankle dorsiflexion. We conclude that QMT shows greater reliability and is easier to implement than MMT. Consequently, QMT will be a superior measure of strength for use in pediatric, neuromuscular, multicenter clinical trials.
TL;DR: It is concluded that a graded exercise test with 3-min stages and 35-W increments is a method by which reproducible measurements of both GE and EC can be obtained, whereas measurements of DE seemed slightly more variable.
Abstract: MOSELEY, L., and A. E. JEUKENDRUP. The reliability of cycling efficiency. Med. Sci. Sports Exerc., Vol. 33, No. 4, 2001, pp. 621‐ 627. Purpose: The aim of this experiment was to establish the reproducibility of gross efficiency (GE), delta efficiency (DE), and economy (EC) during a graded cycle ergometer test in seventeen male subjects. Methods: All subjects performed three identical exercise tests at a constant pedal cadence of 80 rpm on an electrically braked cycle ergometer. Energy expenditure was estimated from
TL;DR: In this paper, a technique combining a universal generating function (UGF) method used for fast reliability estimation of MSS and a genetic algorithm (GA) used as an optimization engine is presented.
Abstract: Usually engineers try to achieve the required reliability level with minimal cost. The problem of total investment cost minimization, subject to reliability constraints, is well known as the reliability optimization problem. When applied to multi-state systems (MSS), the system has many performance levels, and reliability is considered as a measure of the ability of the system to meet the demand (required performance). In this case, the outage effect will be essentially different for units with different performance rate. Therefore, the performance of system components, as well as the demand, should be taken into account. In this paper, we present a technique for solving a family of MSS reliability optimization problems, such as structure optimization, optimal expansion, maintenance optimization and optimal multistage modernization. This technique combines a universal generating function (UGF) method used for fast reliability estimation of MSS and a genetic algorithm (GA) used as an optimization engine. The UGF method provides the ability to estimate relatively quickly different MSS reliability indices for series-parallel and bridge structures. It can be applied to MSS with different physical nature of system performance measure. The GA is a robust, universal optimization tool that uses only estimates of solution quality to determine the direction of search. Copyright © 2001 John Wiley & Sons, Ltd.