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PubMed2001

Internal consistency, temporal stability, and reproducibility of individual index scores of the Test of Variables of Attention in children with attention-deficit/hyperactivity disorder.

Psychometric properties of the Test of Variables of Attention (TOVA) were examined in a cohort of children (n=63) strictly diagnosed with attention-deficit/hyperactivity disorder (AD/HD). Internal consistency was assessed via correlational analyses to determine the degree of agreement among various test portions. The temporal stability of errors of omission, errors of commission, response time, and response time variability was evaluated using test-retest reliability. Reproducibility of individual scores for the same indices was assessed using the Bland-Altman procedure. Select TOVA index scores exhibited high internal consistency in this cohort. Although the temporal stability of group scores (test-retest reliability) was satisfactory, individual test scores were less reproducible. Temporal stability and individual test-retest score agreement were greater for response time and response time variability than for errors of omission and errors of commission.

Journal Article↗
PubMed1996

Predictive validity and internal consistency of the pre-hospital index measured on-site by physicians.

Physiological measures of injury are used as triage tools to identify patients that require treatment in trauma centres. The Pre-Hospital Index (PHI) is based on systolic blood pressure, pulse, respiratory rate, (level of) consciousness, and presence of penetrating injury. The present study evaluated the validity and internal consistency of the PHI. The study was based on 628 patients assessed by physicians at the scene. Mean age was 38.7 years (SD = 24.8), and 65% were male. Motor vehicle collisions caused the injury for 45%. The majority had head/neck (56%) and extremity (45%) injuries. Mean PHI was 4.62 (SD = 5.77), 40% had a PHI of zero, 6% between 1 and 3, 32% between 4 and 7, and 21% greater than 7. The associations between PHI and rates of hospital admission, surgery, ICU treatment, mortality, duration of hospitalization, and length of ICU stay were significant (p < 0.001). A total of 260 (41.4%) patients had major trauma requiring treatment at a trauma centre. A PHI > 3 had 83% sensitivity and 67% specificity for identifying these patients. Internal consistency of the PHI variables was above the acceptable limits. This study has shown that the PHI is a valid and reliable physiological measure of injury severity and field triage tool.

Accidents, Traffic↗
PubMed1998

Testing internal consistency and construct validity during evaluation of performance in a patient simulator.

UNLABELLED: The primary goal of this study was to test the items in a rating system developed to evaluate anesthesiologists' performance in a simulated patient environment. A secondary goal was to determine whether the test scores could discriminate between resident and staff anesthesiologists. Two 5-item clinical scenarios included patient evaluation and induction and maintenance of anesthesia. Rating scales were no response to the problem (score = 0), compensating intervention (score = 1), and corrective treatment (score = 2). Internal consistency was estimated using Cronbach's coefficient alpha. Scores between groups were compared using the Cochran-Mantel-Haenszel test. Subjects consisted of 8 anesthesiology residents and 17 university clinical faculty. The Cronbach's coefficient alpha was 0.27 for Scenario A and 0.28 for Scenario B. Two items in each scenario markedly decreased internal consistency. When these four items were eliminated, Cronbach's coefficient alpha for the remaining six items was 0.66. Faculty anesthesiologists scored higher than residents on all six items (P < 0.001). A patient simulator-based evaluation process with acceptable reliability was developed. IMPLICATIONS: The reliability of anesthesia clinical performance in a patient simulation environment was assessed in this study. Of 10 items, 4 were poor in the evaluation process. When these items were removed, the reliability of the instrument improved to a level consistent with other studies. Because faculty scored higher than resident anesthesiologists, the instrument also showed discriminant validity.

Adult↗
PubMed1998

The Awareness Questionnaire: factor structure and internal consistency.

Patients with traumatic brain injuries often show impaired awareness of their impairments. This impaired awareness can decrease motivation for treatment and limit eventual functional outcome. The importance of this phenomenon has led to the development of multiple techniques and scales for measuring impaired awareness. The present paper briefly reviews the various methods of operationalizing impaired awareness and describes a new scale (the Awareness Questionnaire) designed to incorporate all these methods. Findings of previous studies supporting the validity of the Awareness Questionnaire are presented. The present investigation examined the factor structure and internal consistency of the Awareness Questionnaire with samples of 126 traumatic brain injury survivors and 75 family members/significant others. Principal components factor analysis with varimax rotation indicated three factors: cognitive, behavioural/affective, and motor/sensory. Investigation of internal consistency (Cronbach Coefficient Alpha) in both the patient and family sample yielded satisfactory results. These findings are supportive of continued use and investigation of the Awareness Questionnaire.

Activities of Daily Living↗
PubMed2005

The Swedish Demand-Control-Support Questionnaire (DCSQ): factor structure, item analyses, and internal consistency in a large population.

AIM: This paper examined the psychometric properties of the Swedish Demand-Control-Support Questionnaire (DCSQ), which is a shorter and modified version of Karasek's Job Content Questionnaire (JCQ). METHODS: The study encompassed 5,227 workers born in 1953-57 from the population-based Hordaland Health Study. DCSQ, a 17-item questionnaire, covers psychological demands, decision latitude, and social support in the workplace. The workers were manually classified according to the Standard Classification of Occupations. The main statistical methods were principal component analyses, and estimation of internal consistency and the subscales' shared variance by Cronbach's coefficient a and Pearson's correlation coefficients, respectively. RESULTS: The study gave support to the tri-dimensional factor structure of DCSQ. Decision latitude tended to split into skill discretion and decision authority in skill-level homogeneous samples. The specificity of the item loadings was satisfactory except for "conflicting demands". The inter-correlation of the three main subscales was weak. The internal consistency of the subscales was generally satisfactory. CONCLUSIONS: The psychometric properties of DCSQ are satisfactory. Being shorter and easier to use than the more comprehensive JCQ, DCSQ represents an important alternative, particularly if respondent burden and data-collection costs need to be minimized.

Female↗
PubMedDate not supplied

[Factorial structure and internal consistency of the psychiatric evaluation scale of Krawiecka].

An analysis of internal consistency and factorial structure of Krawiecka's Psychiatric Evaluation Scale was carried out. Global alpha coefficient was found to be 0.36. Factorial analysis revealed the presence of three factors that accounted for 60% of total variance. Factor one included blunted-incongruent affect, poverty of speed and psychomotor retardation. Factor two loaded on delusions, hallucinations and anxiety-agitation and the third factor on incoherent-irrelevant speech and depression.

Adolescent↗
PubMed2005

The validity of the SRS-22 instrument in an adult spinal deformity population compared with the Oswestry and SF-12: a study of response distribution, concurrent validity, internal consistency, and reliability.

STUDY DESIGN: Prospective analysis of a consecutive cohort of adult spinal deformity patients queried over a 12-month period. OBJECTIVES: To assess the SRS-22 instrument compared with the SF-12 and Oswestry. SUMMARY OF BACKGROUND DATA: Very few reports in the literature have applied the SRS-22 to adult spinal deformity patients. METHODS: Consecutive adult spinal deformity patients were applied the SRS-22, SF-12, and Oswestry. Four analyses were done: 1) floor/ceiling effect; 2) Pearson's correlation coefficients between the SRS-22, SF-12, and Oswestry; 3) Cronbach's alpha analysis for internal consistency within the SRS-22; and 4) test/retest. RESULTS: Floor/ceiling range for the SRS-22 compared favorably with the SF-12 and Oswestry. The Pearson's coefficients correlating the two questionnaires relative to the SRS-22 were > 0.7. The Cronbach's alpha within each domain for the SRS-22 were > 0.7, except for pain (0.67). Test/retest correlation coefficients ranged from 0.84 to 0.95 for the subscales. CONCLUSIONS: The SRS-22 is a disease-specific instrument with the capacity to demonstrate change in health status more effectively than the SF-12 and in more domains than the Oswestry. The SRS-22 showed high criterion validity with the SF-12 and Oswestry based on Pearson's coefficients. High Cronbach's alpha scores suggested a high internal consistency within each domain of the SRS-22, except for pain (0.67). Test/retest reliability was excellent.

Adolescent↗
PubMed2001

Hospital Anxiety and Depression (HAD) scale: factor structure, item analyses and internal consistency in a large population.

BACKGROUND: The Hospital Anxiety and Depression (HAD) rating scale is a commonly used questionnaire. Former studies have given inconsistent results as to the psychometric properties of the HAD scale. AIMS: To examine the psychometric properties of the HAD scale in a large population. METHOD: All inhabitants aged 20-89 years (n=92 100) were invited to take part in The Nord-Trøndelag Health Study, Norway. A total of 65 648 subjects participated, and only completed HAD scale forms (n=51 930) formed the basis for the psychometric examinations. RESULTS: Principal component analysis extracted two factors in the HAD scale that accounted for 57% of the variance. The anxiety and depression sub-scales shared 30% of the variance. Both subscales were found to be internally consistent, with values of Cronbach's coefficient (alpha) being 0.80 and 0.76, respectively. CONCLUSIONS: Based on data from a large population, the basic psychometric properties of the HAD scale as a self-rating instrument should be considered as quite good in terms of factor structure, intercorrelation, homogeneity and internal consistency.

Adult↗
PubMed1989

Internal consistency reliability of the fractionated and whole University of Pennsylvania Smell Identification Test.

The internal consistency reliability (ICR) of the 40-item University of Pennsylvania Smell Identification Test (UPSIT) and its 10-, 20-, and 30-item fractions was explored, as well as the relationships between the fractions and the entire 40-item test. Pearson correlation coefficients (rs) were computed among all independent combinations and permutations of the four 10-item UPSIT booklets using data from 774 subjects. The median r values of the 10- and 20-item combinations were used to establish the ICRs of the 10- and 20-item tests. The ICRs of the 30- and 40-item tests were estimated using the Spearman-Brown formula and the median rs of the 20-item combinations. Additional ICR estimates of the 40-item UPSIT were obtained from nonsymmetrical fractions using the Horst formula. The ICRs for the UPSIT and its 10-, 20-, and 30-item fractions were 0.922, 0.752, 0.855 and 0.898, respectively. No major sex differences emerged. Estimates of correlations between (1) single booklets and two-booklet combinations and (2) the 40-item UPSIT using Guilford's (1953) correction for nonindependence ranged from 0.812 to 0.871. Overall, these results indicate that (1) the UPSIT and its 10-, 20-, and 30-item fragments have very high ICRs and (2) individual UPSIT booklets or their combinations can be used to assess smell function in a reliable manner where extreme time constraints are present (e.g., in surveys and in brief neuropsychological test batteries).

Adult↗
PubMed1985

Internal consistency of the short-form of the Questionnaire on Resources and Stress.

The internal consistency of the short-form of the Questionnaire on Resources and Stress (Holroyd, 1982) was examined using a sample of 189 parents of handicapped and nonhandicapped children. Reliability and factor analysis procedures revealed psychometric weaknesses across scales and a factor structure discrepant with that originally postulated by Holroyd. Eight factors were identified and described. Results were compared with the scale configurations proposed by Holroyd. Positive outcomes were discussed regarding the clinical value of the instrument for assessing stress and resources in families and the 8-factor retention of many, if not all, of the items from the scales of the short form. Suggestions for needed research were presented.

Adaptation, Psychological↗
PubMedDate not supplied

Internal consistency of echocardiographic estimates of the severity of left ventricular outflow obstruction.

To determine their internal consistency, M-mode and Doppler echocardiography were used to estimate the gradient across the left ventricular outflow tract during 74 evaluations of 50 infants, children, and young adults with congenital valvular (n = 43), subvalvular (n = 6), and supravalvular (n = 1) aortic stenosis. By M-mode the gradient was estimated from the wall-stress formula (left ventricular pressure = 225 x wall thickness/end-systolic diameter) minus systolic blood pressure determined by sphygmomanometry. Doppler (pulsed or continuous wave) methods utilized the Bernoulli formula (gradient = 4 x V2). There was good agreement between the M-mode and Doppler estimates of outflow gradient in most patients (r = 0.69, standard error of the estimate = 26.9). In 46 of 74 comparisons (62%) the two estimates differed by less than 20 mm Hg, and the estimates placed the patient in the same clinical class (mild, moderate, or severe). In 22 patients undergoing cardiac catheterization, there was only a fair correlation between the M-mode (r = 0.50) and Doppler (r = 0.58) gradients and those obtained at catheterization. Each noninvasive technique yielded major overestimates or underestimates of the gradient in several instances. The M-mode and Doppler techniques for estimating the severity of congenital aortic stenosis are complementary. Their combined use minimizes but does not totally eliminate errors of overestimation or underestimation of outflow gradient.

Adolescent↗
PubMed2000

Coefficient alpha and related internal consistency reliability coefficients.

The author studied the conditions under which coefficient alpha and 10 related internal consistency reliability coefficients underestimate the reliability of a measure. Simulated data showed that alpha, though reasonably robust when computed on n components in moderately heterogeneous data, can under certain conditions seriously underestimate the reliability of a measure. Consequently, alpha, when used in corrections for attenuation, can result in nontrivial overestimation of the corrected correlation. Most of the coefficients studied, including lambda 2, did not improve the estimate to any great extent when the data were heterogeneous. The exceptions were stratified alpha and maximal reliability, which performed well when the components were grouped into two subsets, each measuring a different factor, and maximized lambda 4, which provided the most consistently accurate estimate of the reliability in all simulations studied.

Humans↗
PubMed2000

International assessment of the internal consistency of respiratory symptoms. European Community Respiratory Health Study (ECRHS).

We aimed to assess cross-cultural validity of the reporting of respiratory symptoms in the European Community Respiratory Health Study (ECRHS). A random sample of subjects from the general population (aged 20-44 yr), from 35 centers in 15 countries, answered a questionnaire and underwent allergy tests and airway challenge with methacholine. The overall response rate to the questionnaire was 60% (n = 16,635). Exploratory factor analysis was used to identify how symptoms were grouped (i.e., to specify factor structure), using data from the United Kingdom. Subsequently, a confirmatory factor analysis of the prespecified structure for the United Kingdom was assessed for each country in consecutive nested models, increasing at each step the number of parameters forced to be equal to the United Kingdom, and assessing the goodness of fit. Variables were clustered in the same four groups (factors) in all countries. The four factors, mutually adjusted, were associated with either bronchial responsiveness, atopy, or smoking, which provides coherence for the separation of the four factors. In the confirmatory factor analysis, when the load of each of the symptoms in the corresponding factor was prespecified, all countries except Spain showed an adequate fit; in Spain there were differences in answers concerning asthma treatment. We conclude that the ECRHS multilingual translated respiratory symptoms questionnaire shows high internal consistency, suggesting that international comparisons are not affected by errors due to cross-cultural variations in the reporting of symptoms.

Adult↗
PubMed1994

An examination of the internal consistency and factor structure of the eating disorder inventory-2 in a clinical sample.

We examined the internal consistency and factor structure of the newly revised version of the Eating Disorder Inventory (EDI), with particular emphasis on the examination of the three new provisional scales: Asceticism, Impulse Regulation, and Social Insecurity. Subjects were 300 women who were seeking treatment at a residential treatment facility for women with eating disorders. Chronbach's alphas ranged from .80 to .91 for the eight original scales whereas coefficients for the three new scales were all less than .80, the criterion stated as being necessary for inclusion in the test. Item-total correlations were also substantially lower for the three new scales. The results of principal components analyses with orthogonal rotation supported the factor structure of the original 64-item EDI, but not the three additional scales. These data generally supported the reliability and factor structure of the original eight scales but did not support the reliability or validity of the three provisional scales.

Adolescent↗
PubMed2000

An Internally Consistent Thermodynamic Model for the System CaO-MgO-Al2O3-SiO2 Derived Primarily from Phase Equilibrium Data.

An internally consistent thermodynamic model for the subsolidus system CaO-MgO-Al2O3-SiO2 (CMAS) was developed and refined using primarily data from phase equilibrium experiments. The solution properties of pyroxenes and garnet were approximated with an ionic model, with independent mixing on adjacent crystallographic sites. This approach simplified the calculation of phase relations by allowing sequential calculation of the site occupancies. Enthalpy, entropy, and volume differences, nominally at 970 K, were derived for all participating phases by matching as closely as possible the experimentally observed phase relations. Although thermochemical measurements were not used directly in the refinement, the results were continuously monitored and compared with the thermochemical data to achieve a close match. The new model can be used to calculate phase diagrams for the CMAS system and its subsystems in the whole pressure range of the upper mantle. Simple empirical corrections for the effects of Na, Fe, Cr, etc., could potentially be introduced to make the model applicable to the thermobarometry of chemically complex mantle materials. Application of the new model to garnet lherzolite xenoliths from northern Lesotho and garnet peridotites from Norway supports the proposals for higher temperatures of the continental lithosphere.

Journal Article↗
PubMed2004

Factor structure and internal consistency of the Spanish version of the Gordon Test of Visual Imagery Control.

We examined the factor structure and internal consistency of the Spanish version of the Gordon Test of Visual Imagery Control, as well as the correlations with scores on the Vividness of Visual Imagery Questionnaire and the Verbalizer-Visualizer Questionnaire, for a sample of 479 undergraduates. Principal components analysis, followed by varimax orthogonal rotation, identified the expected four factors (Movement, Misfortune, Colour, and Stationarity), which jointly explained 55% of the variance. The Gordon Test had a Cronbach alpha value of .69 and correlated significantly with scores on Marks' Vividness of Visual Imagery Questionnaire.

Adult↗