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PubMedDate not supplied

[Evaluation of the quality of life of schizophrenic patients: validation of the brief version of the Quality of Life Interview].

UNLABELLED: The main objective of the study was to determine the psychometric properties (mainly, validity and reliability) of the French language version of the brief Quality of Life Interview (QoLI). That instrument evaluates both the subjective and objective aspects of quality of life. METHODS: 128 patients fulfilling the DSM IV criteria for schizophrenia were included. Quality of life was evaluated using the brief QoLI. Schizophrenic symptoms were evaluated using the Positive and Negative Syndrome Scale (PANSS). The validity of the internal structure of the QoLI was investigated by means of item analysis, study of the correlations between the items and between the item-dimensions and principal component analysis addressing the subjective fields. The validity of the external structure was mainly investigated through the nomological validity study. The reliability of the scale was evaluated by studying the internal consistency. In addition, the acceptability of the scale was documented. RESULTS: The results of the study of the validity of the internal structure confirmed the pertinence of the pre-defined fields, particularly the subjective fields. Only some of the subjective fields of the QoLI showed significant correlations with the PANSS sub-scales. The acceptability of the scale was satisfactory. CONCLUSIONS: The psychometric properties of the French language version of the brief QoLI appeared satisfactory. The brief QoLi was shown to be an easily used instrument for assessment of the various objective and subjective aspects of the quality of life of schizophrenic patients.

Adult↗

PubMed1995

[The sophisticated process of validation]

Current concepts on the efficient performance of validation studies are summarized. From the experience of recent attempts to validate alternative methods to animal experiments, the difficult procedure of validation should be refined. The applications of toxicological tests (safety testing) and pharmacological methods (identification of putative drugs) require different validation stategies. Suggestions as to an improved design of test development, evaluation, prevalidation, definitive validation as well as final assessment of the result are presented.

Journal Article↗

PubMed2001

The development and validation of a dysphagia-specific quality-of-life questionnaire for patients with head and neck cancer: the M. D. Anderson dysphagia inventory.

OBJECTIVE: To design a reliable and validated self-administered questionnaire whose purpose is to assess dysphagia's effects on the quality of life (QOL) of patients with head and neck cancer. DESIGN: Cross-sectional survey study. METHODS: Focus groups were convened for questionnaire development and design. The M. D. Anderson Dysphagia Inventory (MDADI) included global, emotional, functional, and physical subscales. One hundred consecutive adult patients with a neoplasm of the upper aerodigestive tract who underwent evaluation by our Speech Pathology team completed the MDADI and the Medical Outcomes Study 36-Item Short Form Health Survey (SF-36). Speech pathologists completed the Performance Status Scale for each patient. Validity and reliability properties were calculated. Analysis of variance was used to assess how well the MDADI discriminated between groups of patients. RESULTS: The internal consistency reliability of the MDADI was calculated using the Cronbach alpha coefficient. The Cronbach alpha coefficients of the MDADI subscales ranged from 0.85 to 0.93. Test-retest reliability coefficients of the subscales ranged from 0.69 to 0.88. Spearman correlation coefficients between the MDADI subscales and the SF-36 subscales demonstrated construct validity. Patients with primary tumors of the oral cavity and oropharynx had significantly greater swallowing disability with an adverse impact on their QOL compared with patients with primary tumors of the larynx and hypopharynx (P<.001). Patients with a malignant lesion also had significantly greater disability than patients with a benign lesion (P<.001). CONCLUSIONS: The MDADI is the first validated and reliable self-administered questionnaire designed specifically for evaluating the impact of dysphagia on the QOL of patients with head and neck cancer. Standardized questionnaires that measure patients' QOL offer a means for demonstrating treatment impact and improving medical care. The development and validation of the MDADI and its use in prospective clinical trials allow for better understanding of the impact of treatment of head and neck cancer on swallowing and of swallowing difficulty on patients' QOL.

Adult↗

PubMed2001

Predictive validity of the Addiction Severity Index's composite scores in the assessment of 2-year outcomes in a methadone maintenance population.

The current research tested the predictive validity of 6 of the 7 Composite Scores (CSs) of the Addiction Severity Index (ASI) in 310 methadone maintenance patients assessed at treatment entry using the ASI and other measures, and followed for 2 years. Logistic regression was used to estimate the sensitivity and specificity of the CSs at intake in predicting their respective validity criterion measures at follow up. Except for the Medical CS, each of the other 5 CS measures significantly predicted its validity criterion measure. The CSs measuring drug use, alcohol abuse, psychopathology, and legal problems had high specificity (88% [corrected] for the Drug CS, 91% for the Alcohol CS, 96% for the Legal CS, and 100% for the Psychological CS). The CSs measuring employment problems had high sensitivity (76%). The results support the predictive validity of most of the ASI CSs as measures of specific problems as well as the validity of the multidimensional construct on which the ASI is based.

Adult↗

PubMed2001

Validation of an instrument to measure dental students' use of, knowledge about, and attitudes towards computers.

Currently, no validated survey instrument exists to measure dental students' use of, knowledge about, and attitudes towards computers. Several studies have surveyed students about their knowledge and opinions regarding computers, but none of them has established the reliability and validity of the instrument(s) used. A measurement study to validate a preliminary survey for dental students was conducted. The preliminary instrument contained five scales: computer use, information resource use, computer knowledge, capabilities of computer systems, and effects of computers on dental practice. Selected variables were summarized descriptively, and a factor analysis for each scale was performed. In addition, construct validity was assessed through correlational analyses among several variables. Three hundred seventy surveys distributed to students at nine dental schools generated 156 responses (42 percent response rate). Sixty-four percent of respondents were male, 36 percent female. Respondents used computers an average approximately four hours per week, and most had begun using computers in 1991. All survey scales except computer use were unidimensional. Computer use required a two-factor solution that distinguished between clinical and nonclinical uses of computers. The instrument can be used for a demonstration study, but should be continuously refined and validated.

Analysis of Variance↗

PubMed2001

[The European Evaluation of Vertigo (EEV) scale: a clinical validation study].

Up until now, the questionnaires used to evaluate vertigo have been self-administered questionnaires that rate either symptoms and/or their consequences. In contrast, the European Evaluation of Vertigo scale (EEV) is a physician-administered questionnaire that only assesses symptoms of the vestibular syndrome: illusion of movement, duration of illusion, motion intolerance, neurovegetative signs, and instability. Twenty-six ear, nose, and throat (ENT) specialists participated in this validation study conducted among 123 patients suffering from different types of vertigo. The reliability, responsiveness and construct, convergent and discriminant validity of the EEV scale were assessed. Construct, convergent and discriminant validity was determined by comparing the scores on the EEV scale with those obtained using the following validated scales: patient diary and conventional scale designed by the DPHM, functional scale of the AAO-HNS, and SF-36 scale, a generic quality of life scale. With the exception of the "neurovegetative signs" item, the reliability of the EEV scale is good, particularly in terms of interrater reliability (r = 0.93 for the global score), and responsiveness is high (p < 0.01). EEV scale has good correlations with the items of patient diary, DPHM scale and "physical" dimensions of SF-36, from the first evaluation, whereas this scale has poor correlation at Day 0, with the items of AAO scale and the "psychological" dimensions of SF-36. These results confirm that EEV scale is exclusively a symptomatic scale and does not interfere with the psychism. The EEV scale is therefore a validated physician-administered questionnaire capable of monitoring the course of vertigo and of assessing the efficacy of anti-vertigo treatments.

Adolescent↗

PubMed2002

International Study of Asthma and Allergies in Childhood (ISAAC): validation of the written questionnaire (eczema component) and prevalence of atopic eczema among Brazilian children.

Although Hanifin and Rajka's criteria have been used for the diagnosis of atopic eczema (AE), there is no instrument destined for epidemiological studies on AE that actually uses them. Written questionnaires (WQ) have generally been used, but when translated into another language they must be validated. The Intemational Study of Asthma and Allergies in Childhood (ISAAC) WQ was previously validated in a comprehensive study, but its validation in Brazil had not been done. Our objective was to validate the eczema component of the self-applicable ISAAC's WQ following its translation into Portuguese. The group of 10 pediatricians and 10 pediatric allergologists graded the questions from 0 to 2 and established the maximum score for each question. The WQ was answered by parents or guardians of children with atopic dermatitis (AE), aged 6-7 years (n = 23) and of non-AE control children of the same age (n = 46) as well as by AE (n = 24) and non-AE (n = 48) adolescents, aged 13-14 years. In order to evaluate the reproducibility of the ISAAC WQ, half of these individuals answered the same questionnaire after 2 to 4 weeks. The maximum possible global scores were 13 for the children aged 6-7 years and 11 for the adolescents, and the cutoff level for both groups was 3. In both age periods the WQ was reproducible (Kappa and McNemar tests) in a significant way (6-7 years, Kw = 0.79; 13-14 years, Kw = 0.73). The prevalence of AE, using the validated WQ, was then studied. The WQ was applied to the parents of 3,005 children aged 6-7 years and to 3008 children aged 13-14 years. Response rates were 72% and 94% for the 6-7-year-old children and the 13-14-year-old children, respectively. There was a slight predominance of male children in the studied population. In the group of the 6-7-year-old children, the cumulative prevalence of AE was 13.2% for boys and for girls; in the group of the 13-14-year-old children, it was 12.5% and 15.4%, respectively. AE severity was similar for both age groups. Using the criteria of global cutoff score, in the group of the 6-7-year-old children, the prevalence of AE was 12.6% for boys and 13.8 for girls; in the group of the 13-14-year-old children, it was 11.7% and 12.4%, respectively. There were no significant differences between them. In conclusion, the AE component of the ISAAC WQ proved to be reproducible, adequate, and able to discriminate between AE and control children. A significant concordance was observed between the criteria utilized in this study (ISAAC x global cutoff score).

Adolescent↗

PubMed2001

Functional capacity evaluation: Ecological validity of three static endurance tests.

Functional Capacity Evaluation's (FCE's) are designed to measure the functional capacity of injured workers. Static endurance tests are integrated aspects of FCE's. Little is known about the validity of the tests. In this study, three static endurance tests (overhead work, crouching and kneeling) of the Isernhagen Work Systems FCE are studied for ecological validity. By manipulating the environment in an experiment using three different conditions (normal, loud noise, high production requirement), the ecological validity of the tests was investigated. Results: the different conditions did not seem to influence the holding times, the perceived exertion and the productivity of the subjects. The results are discussed and it is concluded that the three static endurance tests meet conditions of ecological validity. In order to be able to state that the tests of the IWS FCE are ecologically valid, more research is needed to enable a generalization.

Journal Article↗

PubMedDate not supplied

Examining the validity, reliability, and preference of three pediatric pain measurement tools in African-American children.

PURPOSE: To compare the validity, reliability, and preference of pain intensity measurement tools--the African-American Oucher Scale, the Wong-Baker FACES Scale, and the Visual Analog Scale (VAS)--in 100 African-American children between 3 and 18 years of age. METHODS: During a visit to the sickle cell anemia clinic, the children were asked to describe two painful procedures/treatments they had experienced and to choose which one hurt the most. They rated the pain intensity of each procedure/treatment on the three scales that were presented in a preselected order. After using all the scales, the children then chose their favorite scale. The same procedure was repeated at the end of the visit, with a minimum of 15 minutes between the test and retest. RESULTS: Concurrent validity was determined by comparing the rank order of the two identified painful items with the pain scores on the three scales. Chi square analysis indicated a statistically significant difference among the scales for preference (chi2 = 24.08, df = 2, p < 0.0001) and reliability (chi2 = 6.12, df = 2, p < 0.05), but not validity (chi2 = 0.81, df = 2, NS) for the entire sample. Most children preferred using the FACES Scale (56%) versus the Oucher (26%) and VAS (18%). When the data were analyzed for three cognitive stages (ages 3-7, 8-12, and 13-18 years), the following were found: For the school-age period, chi square for reliability did not reach significance (chi2 = 4.35, df = 2, NS); for the preschool-age period, chi square for validity did reach significance (chi2 = 6.49, df = 2, p < 0.05) and was strongest for the FACES scale, followed by the Oucher. CONCLUSIONS: The study findings indicated that the FACES and African-American Oucher Scales are valid and reliable tools for measuring pain in children. Among the entire sample and each age group, the FACES scale was the most preferred scale.

Adolescent↗

PubMed2002

Implementation of three Rs alternatives in regulatory testing: possibilities and obstacles--the view of the validator.

After the establishment of the European Centre for the Validation of Alternative Methods (ECVAM) in 1993, the Scientific Advisory Committee (ESAC) decided at its first meeting that the implementation of the Three Rs in the production and quality control of biologicals should be one of ECVAMs priorities. In collaboration with experts, ECVAM has established guidelines on the pre-validation and validation of alternative toxicological methods, which are as applicable to alternative methods in the quality control of biologicals as they are to the testing of industrial chemicals. This paper explains the technical information which should be submitted to ECVAM to assess the readiness of a method for pre-validation, which is defined as a small-scale interlaboratory study to confirm that an optimised and transferable protocol is available. Where appropriate, a formal validation study is then conducted, to evaluate the scientific relevance and reliability of the test method.

Animal Testing Alternatives↗

PubMed2003

Assessing reliability and validity measures in managed care studies.

BACKGROUND: To review the reliability and validity literature and develop an understanding of these concepts as applied to managed care studies. RESULTS: Reliability is a test of how well an instrument measures the same input at varying times and under varying conditions. Validity is a test of how accurately an instrument measures what one believes is being measured. METHODS: A review of reliability and validity instructional material was conducted. CONCLUSIONS: Studies of managed care practices and programs abound. However, many of these studies utilize measurement instruments that were developed for other purposes or for a population other than the one being sampled. In other cases, instruments have been developed without any testing of the instrument's performance. The lack of reliability and validity information may limit the value of these studies. This is particularly true when data are collected for one purpose and used for another. The usefulness of certain studies without reliability and validity measures is questionable, especially in cases where the literature contradicts itself

Data Interpretation, Statistical↗

PubMed2003

Evidence for the Factorial and Construct Validity of a Self-Report Concussion Symptoms Scale.

OBJECTIVE: To evaluate the factorial and construct validity of the Head Injury Scale (HIS) among a sample of male and female collegiate athletes. DESIGN AND SETTING: Using a cross-sectional design, we established the factorial validity of the HIS scale with confirmatory factor analysis and the construct validity of the HIS with Pearson product moment correlation analyses. Using an experimental design, we compared scores on the HIS between concussed and nonconcussed groups with a 2 (groups) x 5 (time) mixed-model analysis of variance. SUBJECTS: Participants (N = 279) in the cross-sectional analyses were predominately male (n = 223) collegiate athletes with a mean age of 19.49 +/- 1.63 years. Participants (N = 33) in the experimental analyses were concussed (n = 17) and nonconcussed control (n = 16) collegiate athletes with a mean age of 19.76 +/- 1.49 years. MEASUREMENTS: All participants completed baseline measures for the 16-item HIS, neuropsychological testing battery, and posturography. Concussed individuals and paired controls were evaluated on days 1, 2, 3, and 10 postinjury on the same testing battery. RESULTS: Confirmatory factor analysis indicated that a theoretically derived, 3-factor model provided a good but not excellent fit to the 16-item HIS. Hence, the 16-item HIS was modified on the basis of substantive arguments about item-content validity. The subsequent analysis indicated that the 3-factor model provided an excellent fit to the modified 9-item HIS. The 3 factors were best described by a single second-order factor: concussion symptoms. Scores from the 16-item HIS and 9-item HIS were strongly correlated, but there were few significant correlations between HIS scores and scores from the neuropsychological and balance measures. A significant group-by-day interaction was noted on both the 9-item HIS and 16-item HIS, with significant differences seen between groups on days 1 and 2 postconcussion. CONCLUSIONS: We provide evidence for the factorial and construct validity of the HIS among collegiate athletes. This scale might aid in return-to-play decisions by physicians and athletic trainers.

Journal Article↗

PubMed2003

Interrater reliability and content validity of a minimal data set to measure outcomes of students receiving school-based occupational therapy and physical therapy.

BACKGROUND AND PURPOSE: The 1997 Amendments of the Individuals with Disabilities Education Act increased the emphasis on accountability for outcomes of students with disabilities in the United States. The purpose of this study was to determine the content validity and estimate the interrater reliability of the School Outcomes Measure, a new minimal data set to measure groups of students' performance in the areas addressed by school-based therapy. METHOD: Forty-five occupational therapists and physical therapists working in Oklahoma's public schools participated in the content validity study. Eight occupational therapist-physical therapist pairs rated 17 students for the interrater reliability study. Therapists were recruited and data were collected by mail for both studies. RESULTS: Most validity study participants thought the tool was comprehensive and clear, and that they could complete the tool twice a year for their students. The weighted kappa statistic indicated that the therapists' agreement was substantial (.73) to almost perfect (.96) for 25 of the 28 student functional status items. DISCUSSION: The results support the content validity and interrater reliability of the items. This study was an initial step in development of the tool and further studies are needed in the validation process.

Activities of Daily Living↗

PubMed2003

Validation of fermentation processes.

The ability to prepare consistent biopharmaceutical products depends extensively on possession of banked and characterized cell substrates and on development of production processes which can be validated. While the attributes that define cell characterization have been extensively detailed by ICH and the regulatory agencies in the past decade, little has been specified regarding process validation for biological processes. The extent to which validation concepts can be applied to biological processes varies depending on the nature of the process, the nature of the product, and the level of knowledge regarding the relationship between process parameters and product quality. Expectations concerning the rigour of the validation programme should be adjusted accordingly. There is no single approach that is appropriate for all processes and products. At a minimum, there should be an attempt to define which process parameters are critical, and to focus the attention of validation efforts on these parameters.

Biotechnology↗

PubMed1992

Philosophy and goals of validation for biotech products and the relevance of scale.

A model for validation of viral clearances in Biopharmaceutical processes is developed from an analysis of validation of terminal sterilization processes. The model develops the role for small-scale experiments in the validation of large-scale production processes. The steps for process validation are: identify or discover the basic general physical, chemical, or biological laws governing the process; identify the critical process control parameters for the specific application under investigation; and demonstrate the ability of the production equipment to maintain critical parameters with specified limits. For concurrent validation, this final step is seen as equivalent to demonstrating that a scaled-down model experiment is an appropriate representation of the production process.

Biological Products↗

PubMed1992

Rapid classification of positive blood cultures. Prospective validation of a multivariate algorithm.

OBJECTIVE: To develop and validate a model predicting whether a positive blood culture represents a true positive or a contaminant in hospitalized patients, using only information available when the initial culture result becomes available. DESIGN: Prospective cohort study with derivation and validation sets. SETTING: Urban tertiary care hospital. PATIENTS: Clinical data were collected within 24 hours of the initial culture from a random sample of inpatients who had blood cultures performed, and data from the episodes in which growth was reported were included. There were 219 episodes in the derivation set and 129 episodes in the validation set. MAIN OUTCOME MEASURE: True bacteremia. Reviewers blinded to potential clinical predictors and initial laboratory results classified 115 (53%) of the episodes in the derivation set and 57 (44%) of the episodes in the validation set as true positives. RESULTS: Independent multivariate predictors of bacteremia were organism type, days until the blood culture became positive, multiple positive cultures, and clinical risk score. These factors were used to develop a model stratifying patients into four risk groups. In the derivation set's lowest-risk group, 92% (65/71) of positives represented contaminants, and in the highest-risk group, 97% (86/89) of positives represented true positives. In the validation set, the misclassification rates were 14% (8/59) in the low-risk group, and 11% (5/44) in the high-risk group. These two groups together comprised 76% of all episodes. CONCLUSION: This model can help clinicians quantify the likelihood that a given positive blood culture represents a true positive when the laboratory first calls, which may be helpful in subsequent decision making.

Adult↗

PubMed2004

The valid time of soda lime could be safely prolonged according to the inspired pressure of carbon dioxide.

BACKGROUND: Carbon dioxide (CO2) absorbent, a disposable chemical mixture enclosed in a canister of anesthetic breathing systems functions to remove the carbon dioxide expired from the patients during general anesthesia. The timing of replacing the exhausted CO2 absorbent is usually decided by discoloration of the indicator dye or the valid time of use. However, these methods are subjective. We designed a study to validate our idea of replacing the exhausted CO2 absorbent according to the inspired pressure of carbon dioxide (PiCO2) and comparison of the pressure difference between the arterial carbon dioxide tension (PaCO2) and end-tidal CO2 in the exhausted and fresh CO2 absorbent circuits. METHODS: Fifty-five adult patients undergoing general anesthesia for elective surgeries were enrolled in this study. All the canisters containing fresh soda lime were labeled with the date of filling and valid time of clinical use. The soda lime was replaced only when the PiCO2 reached 6 mmHg. Before and 20 minutes after the replacement, PaCO2 and end-tidal CO2 were obtained and designated as group-Pre and group-Post, respectively. The pressure differences between PaCO2 and end-tidal CO2 in both groups were checked for statistical analysis. RESULTS: The pressure differences in group-Pre and group-Post were 5.8 +/- 3.4 mmHg and 6.1 +/- 3.3 mmHg, respectively, both of which were not statistically significant (P = 0.62). The PaCO2 in group-Pre and group-Post was 43.7 +/- 4.2 mmHg and 40.9 +/- 4.6 mmHg respectively. The end-tidal CO2 in group-Pre and group-Post was 38 +/- 3.5 mmHg and 35 +/- 3.6 mmHg, respectively. There were significant differences in PaCO2 and end-tidal CO2 between the two groups (P < 0.001). By this determination the valid time of soda lime in Omeda, Cato and Kion anesthesia machines was 57.3 +/- 7.2, 35.6 +/- 6.3 and 21.7 +/- 4.2 hours, respectively, all of which were much longer than 8 hours of routine use previously delimited. CONCLUSIONS: Even though the PiCO2 concentration reached 6 mmHg in the rebreathing circuit with exhausted soda lime, the gradient between the PaCO2 and end-tidal CO2 was of no statistical difference compared with that of the fresh soda lime circuit. Thus the pressure difference was not affected by the exhausted CO2 absorbent in spite of a reach of PiCO2 to 6 mmHg. Under CO2 monitoring, the valid time of soda lime could be safely prolonged until the PiCO2 was elevated to 6 mmHg rather than 8 h strictly pursuant to traditional method of discoloration of indicator dye.

Adult↗

PubMed2005

Calibration and validation of multiple regression models for stormwater quality prediction: data partitioning, effect of dataset size and characteristics.

Two main issues regarding stormwater quality models have been investigated: i) the effect of calibration dataset size and characteristics on calibration and validation results; ii) the optimal split of available data into calibration and validation subsets. Data from 13 catchments have been used for three pollutants: BOD, COD and SS. Three multiple regression models were calibrated and validated. The use of different data sets and different models allows viewing general trends. It was found mainly that multiple regression models are case sensitive to calibration data. Few data used for calibration infers bad predictions despite good calibration results. It was also found that the random split of available data into halves for calibration and validation is not optimal. More data should be allocated to calibration. The proportion of data to be used for validation increases with the number of available data (N) and reaches about 35% for N around 55 measured events.

Calibration↗