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PubMedDate not supplied

Screening for speech and language disorders: the reliability, validity and accuracy of the General Language Screen.

This paper reports the reliability, validity and accuracy of the General Language Screen (GLS) as the first stage in its development as a potential screening instrument for the identification of speech and language disorder (SLD) in the primary care setting. Data reported were obtained during the Cambridge Language and Speech Project (CLASP) a longitudinal epidemiological study of primary SLD. The GLS was originally used in initial CLASP sample ascertainment when children were aged 36 months. This report utilises speech and language data collected at subsequent stages of this study (37-months, 45-months and 8-years) to determine the reliability, validity and accuracy of the GLS. The GLS demonstrated sufficient levels of reliability (internal consistency alpha = 0.74) and validity (criterion validity r = -0.55). Adequate construct validity was demonstrated by a factor analysis in which two language related factors were identified. These data therefore justified exploration of the accuracy of the GLS as a screening instrument. Analysis of accuracy in this context is complicated by lack of a generally accepted method of defining SLD case status. This report utilises data on language function at different stages of development to provide measures of GLS accuracy over time. Concurrent accuracy, measured against parental report of language function at 37-months, was good (ROC area under the curve = 0.93). Predictive accuracy measured against direct assessment of speech and language at 45-months and 8-years was, as expected, somewhat less (ROC = 0.77 and 0.68 respectively). The implications for the use of the GLS as a screening instrument are discussed. The data indicate that the GLS would function most usefully as the first stage of a two-stage screen for SLD in the primary care setting. Recommendations are made as to the nature of the second stage of such a screen and plans for future research are outlined.

Child↗

PubMed1980

Validation of gas and vapor sampling methods under field insult conditions.

A technique has been developed to validate gas and vapor sampling methods under field insult conditions. Laboratory validation, a necessary aspect of good laboratory practices, only tests the feasibility of a sampling method. "Field validation" determines the effectiveness of a given sampling method in the actual workplace environment where potentially interfering components may exist. A simple and inexpensive means is shown for introducing a known addition spike onto the sampling device during sampling. The validation sample is subject to the same field conditions as area or personnel samples. Upon analysis, recovery of the known addition spike within specified limits, verifies validity of the day's samples. Insufficient known addition spike recovery alerts the hygienist that something has caused sample failure, resulting in an invalid measurement of worker exposure.

Air Pollutants↗

PubMed2006

Criterion validity of the NC-stat automated nerve conduction measurement instrument.

The purpose of this study is to assess the criterion validity of peroneal and posterior tibial nerve conduction measurements obtained with the NC-stat system. Sixty patients referred to the Boston VA EMG laboratory were enrolled. Each subject had a full study of the lower extremity performed using traditional EMG equipment prior to obtaining the NC-stat measurements. These included peroneal and posterior tibial distal motor latency (DML), amplitude (AMP) and F-wave latency (FLAT) measurements. Excellent criterion validity was demonstrated for the peroneal and posterior tibial FLATs and the peroneal AMP. Acceptable criterion validity was identified in the peroneal DML and the posterior tibial AMP. The validity of the posterior tibial DML could not be demonstrated. With the exception of the peroneal DML, criterion validity was maintained in a sub-group analysis of the 50% most abnormal parameter values. The comparability of NCS performed with the NC-stat and in traditional settings has been demonstrated for motor studies of the median and ulnar nerves in previous studies. This study shows that the technology used by the NC-stat for studying the peroneal and posterior tibial nerves compares favorably as well with that obtained with traditional EMG equipment used under neurologist supervision.

Adolescent↗

PubMed1992

Validation of a screening questionnaire for the detection of epileptic seizures in epidemiological studies.

A large-scale clinico-epidemiological study of epileptic seizures has been carried out in a highland area in northern Ecuador, South America. This paper describes the design and the two-staged validation procedures undertaken to authenticate the screening questionnaire, which was used to detect epileptic seizures in the community during this project. An initial questionnaire consisting of 20 questions was devised and then validated in a group of healthy subjects and a group of patients with known epileptic seizures. This questionnaire was found to have a sensitivity of 100% and a specificity of 50.8%. A cluster analysis of the responses rates was undertaken and a set of nine questions which presented a specificity of 92% and sensitivity of 98% were chosen to be used during the survey. The validation of this nine-question instrument was then undertaken by direct application to a general population of 72,121 persons. Positive, negative, false positive and false negative rates were derived. The screening instrument was found to have a sensitivity of 79.3%, a specificity of 92.9%, a positive predictive value of 18.3%, a negative predictive value of 99.6% and a Youden's index of 0.79. The methodology of the study and the instruments developed are recommended for future neuro-epidemiological work in epilepsy. The problems of validation are discussed, and previous epidemiological studies of epilepsy reviewed with special emphasis on the handling of questions of validation.

Adolescent↗

PubMed1987

General method validation guidelines for pharmaceutical samples.

Method validation guidelines, which provide an organizational structure for the design and evaluation of a validation procedure, are presented for a wide range of pharmaceutical applications. The validation guidelines are based on the analyte concentration/sample matrix combination to which the method will be applied. These guidelines include the selection of appropriate validation parameters, design considerations for evaluation, and a discussion of acceptance guidelines for the determination of acceptable method performance. A set of tables is included which illustrates the selection and testing procedure and tailors the entire validation process to the specific characteristics of the determination to be made.

Chemistry, Pharmaceutical↗

PubMed1984

Construct validity of indicator-scales developed from the Comprehensive Assessment and Referral Evaluation interview schedule.

This paper is an assessment of the construct validity of the scales developed from the Comprehensive Assessment and Referral Evaluation (CARE). Data collected from 445 elderly adults residing in New York and 396 in London were used to develop scales to measure medical, psychiatric, and social problems. Diagnostic and global ratings made by psychiatrists and social scientists provided one source of corroborative information; scales developed from information obtained from a random subsample of 162 collateral sources were used as another method of determining validity. Evidence was provided for convergent and divergent validity using multitrait-multimethod matrices to represent the relationships among scales across methods. Convergent validity coefficients ranged from (.40 to .75) for the CARE scales with the diagnostic ratings and from (.30 to .70) for the informant scales. It is argued that most scales are valid by this criterion.

Activities of Daily Living↗

PubMed2006

Coping with late-life challenges: Development and validation of the care-receiver efficacy scale.

PURPOSE: Measures are lacking that address the challenges that people think they face in their roles as elderly care receivers. However, the development of a sense of efficacy in this role by mentally competent care receivers is critical to successful partnerships between caregivers and care receivers. The purpose of this article is to report the development and psychometric analysis of the Care-Receiver Efficacy Scale (CRES). DESIGN AND METHODS: Content validity, internal consistency reliability, factor structure, and convergent validity were assessed through a pilot study, expert review, and field administration with 177 participants. RESULTS: Results suggest that the CRES comprises five subscales, with strong reliability evidenced for three subscales but marginal reliability for the remaining two. Strong support was found for content validity from expert review and moderate support from the relationship between empirical and expert judgment of item location. Support for validity also was found from correlation with the Geriatric Depression Scale-Short Form and the Philadelphia Geriatric Center Morale Scale. IMPLICATIONS: The CRES may be useful as an outcome measure for psycho-socio-behavioral interventions aimed at increasing the capacity of care receivers to direct and improve their own care. Future measure revision and validation are important to optimize its utility.

Adaptation, Psychological↗

PubMed2005

Prospective validation of two models predicting pregnancy leading to live birth among untreated subfertile couples.

BACKGROUND: Models predicting clinical outcome need external validation before they can be applied safely in daily practice. This study aimed to validate two models for the prediction of the chance of treatment-independent pregnancy leading to live birth among subfertile couples. METHODS: The first model uses the woman's age, duration and type of subfertility, percentage of progressive sperm motility and referral status. The second model in addition uses the result of the post-coital test (PCT). For validation, these characteristics were collected prospectively in two University hospitals for 302 couples consulting for subfertility. The models' ability to distinguish between women who became pregnant and women who did not (discrimination) and the agreement between predicted and observed probabilities of treatment-independent pregnancy (calibration) were assessed. RESULTS: The discrimination of both models was slightly lower in the validation sample than in the original sample which provided the model. Calibration was good: the observed and predicted probabilities of treatment-independent pregnancy leading to live birth did not differ for both models. CONCLUSIONS: The chance of pregnancy leading to live birth was reliably estimated in the validation sample by both models. The use of PCT improved the discrimination of the models. These models can be useful in counselling subfertile couples.

Birth Rate↗

PubMed1996

Validity and reproducibility of alcohol consumption in Italy.

BACKGROUND: The reproducibility and validity of alcohol consumption has not been adequately studied, particularly in mediterranean countries, where alcohol drinking is a widespread habit, especially during meals. METHODS: We compared alcohol consumption measured by two interviewer-administered food frequency questionnaires (FFQ) with average intake derived from two 7-day dietary (7-DD) records (the reference method) on 395 volunteers. Different types of alcoholic beverages were considered separately in order to verify the ability of the questionnaire to assess detailed patterns of alcohol intake. RESULTS: A satisfactory level of reproducibility and validity of the pattern of alcohol consumption across different levels and types of alcoholic beverage intake was observed. The reproducibility of wine and total alcohol intake showed correlation coefficients > 0.75 in both sexes. The validity was somewhat higher for wine (around 0.70) than for other alcoholic beverages and total alcohol intake. This is probably accounted for by the more regular pattern of wine consumption during the year as compared to other alcoholic beverages (beer, grappa, etc) which are more strongly influenced by seasonal and daily variations. However, about 30% of abstainers according to FFQ were drinkers by the reference method. The opposite was observed in only 4% of subjects. CONCLUSION: The FFQ is a reliable and valid instrument for collecting alcohol intake in regular drinkers. Lower validity in irregular drinkers may be due to seasonal variation and/or inadequacy of the FFQ to capture irregular patterns of consumption and/or inadequacy of the average of two 7-DD as a reference method. Furthermore, a considerable degree of misclassification was observed between non-drinkers and moderate drinkers.

Adult↗

PubMed1997

Estimation of reproducibility and relative validity of the questions included in the EPIC Physical Activity Questionnaire.

BACKGROUND: The EPIC core questionnaire on lifestyle contains a number of questions on physical activity designed to rank subjects according to level of physical activity (short PA questionnaire). These questions are based on a more extensive questionnaire designed to measure absolute total energy expenditure (extensive PA questionnaire), that was validated in a pilot study preceding EPIC. Reproducibility and relative validity of the short PA questionnaire were estimated by selecting, from the pilot study data, the answers to a number of questions from the extensive questionnaire that resembled those actually included in the short version. METHODS: The population of the pilot study consisted of 126 men and women aged between 20 and 70 years. Reproducibility was estimated by administering the extensive questionnaire three times: at baseline, and after 5 and 11 months. In order to determine the relative validity of the extensive questionnaire, a 3-day activity diary, repeated four times, was used as the reference method. RESULTS: Over the study period (13 months), mean absolute energy expenditure, estimated from the questions included in the short questionnaire, was fairly constant in men but not in women. REPRODUCIBILITY: Spearman correlation coefficients ranged from 0.47 to 0.89 in men, and from 0.49 to 0.81 in women. RELATIVE VALIDITY: Spearman correlation coefficients between the short questionnaire and the diary were between 0.32 and 0.81 for men, and between 0.28 and 0.72 for women. CONCLUSIONS: The questions selected for the short questionnaire are not suitable for estimating energy expenditure at an absolute level. Reproducibility and relative validity of the ranking of subjects seemed satisfactory and comparable to the extensive questionnaire. The results imply that the short questionnaire is suitable for ranking subjects in the EPIC study.

Adult↗

PubMed1997

Reproducibility and relative validity of food group intake in a food frequency questionnaire developed for the German part of the EPIC project. European Prospective Investigation into Cancer and Nutrition.

BACKGROUND: For the German part of the European Prospective Investigation into Cancer and Nutrition (EPIC), a self-administered, optically-readable food frequency questionnaire (FFQ), including 158 food items and 87 coloured portion size photographs, was developed to assess the usual food and nutrient intake of individuals during the past year. In 1991/1992, the reproducibility and validity of the questionnaire measurements were studied according to the EPIC protocol. This article reports the results on reproducibility and relative validity of measurement of food group intake. METHODS: A total of 104 men and women aged 35-64 years, who are members of the local health insurance institution, AOK Heidelberg, participated in this study. Reproducibility of the questionnaire measurements was obtained by a repeated administration of the FFQ to the same study subjects at a 6-month interval. The mean of 12 24-hour dietary recalls applied at monthly intervals served as reference method for the estimation of the relative validity of questionnaire measurements. A second version of the FFQ that integrated questions on general food consumption patterns was also investigated. RESULTS: Spearman test-retest correlations of food group intake ranged from 0.49 for bread to 0.89 for alcoholic beverages (median = 0.70). Spearman correlations between food group intake values derived from the 24-hour diet recalls and the FFQ completed in the summer of 1992 varied from 0.14 for legumes to 0.90 for alcoholic beverages (median = 0.45). Correction for attenuation due to within-person error in the reference method as well as the correction for general consumption patterns improved the correlations. CONCLUSION: The results indicate that our newly developed FFQ gives reproducible estimates of food group intake. Large day-to-day variation in food group intake complicated the evaluation of FFQ validity. Overall, moderate levels of relative validity were observed for estimates of food group intake.

Adult↗

PubMed2006

The development and validation of the Concise Outpatient Department User Satisfaction Scale.

OBJECTIVE: To develop and validate a concise scale for measuring outpatient satisfaction suitable across specialties and cultures. DESIGN: & SETTING: Item generation adopted a concept-driven approach, and 10 candidate items were administered together with a battery of validation items and scales in a cross-sectional survey at a government-aided Chinese medicine specialized outpatient department in Hong Kong. PARTICIPANTS: About 344 consenting patients or their accompanying caregivers were recruited upon their first visit at the clinic and interviewed one month thereafter. RESULTS: The overall response rate was 79%. After deleting one item (physician's manner and attitude) for its redundancy suggested by interitem correlations, exploratory factor analysis yielded two factors, General Service and Case Physician, explaining 75% of variance of the remaining nine items. The internal consistency coefficients of the whole scale and the two subscales were higher than 0.90. Criterion-related validity was supported by high correlations with three anchor items, overall satisfaction, intended future reutilization, and recommendation to others (r = 0.38-0.85). Significant correlations with compliance and negative affects provided preliminary evidence for construct validity. CONCLUSION: The psychometric properties of the resulting 9-item scale supported its usefulness in measuring outpatient satisfaction. Further validation studies in various specialties and countries are suggested to make future cross-cultural comparisons possible.

Adult↗

PubMed1995

Validation of the Radimer/Cornell measures of hunger and food insecurity.

Hunger and food insecurity have been identified as core indicators of an individual's nutritional state that should be assessed in nutrition surveillance activities. Such an assessment requires a valid measure of these phenomena. This paper describes further work on the construction of measures of hunger and food insecurity based on the Radimer/Cornell items and provides an assessment of their validity. A random sample survey of 193 households with women and children living at home was conducted in 1993 in a rural county in New York State. A questionnaire containing the Radimer/Cornell hunger and food insecurity items, information about demographic characteristics, frequency of fruit and vegetable consumption, and household food supplies was administered to subjects. Measures were constructed that identified households experiencing household- and individual-level food insecurity and households with hungry children. The construct and criterion-related validity of the measures was assessed. In relation to criterion-related validity, as food insecurity worsened, there was a significant and progressive increase in the percentage of subjects participating in food programs and having low income, education and employment and a significant decline in average household food availability and fruit and vegetable consumption. These results support the validity of the Radimer/Cornell measures and illustrate their ability to differentiate among groups of households experiencing increasingly severe food insecurity and hunger.

Adolescent↗

PubMed1990

Validation of intermediate end points in cancer research.

Investigations using intermediate end points as cancer surrogates are quicker, smaller, and less expensive than studies that use malignancy as the end point. We present a strategy for determining whether a given biomarker is a valid intermediate end point between an exposure and incidence of cancer. Candidate intermediate end points may be selected from case series, ecologic studies, and animal experiments. Prospective cohort and sometimes case-control studies may be used to quantify the intermediate end point-cancer association. The most appropriate measure of this association is the attributable proportion. The intermediate end point is a valid cancer surrogate if the attributable proportion is close to 1.0, but not if it is close to 0. Usually, the attributable proportion is close to neither 1.0 nor 0; in this case, valid surrogacy requires that the intermediate end point mediate an established exposure-cancer relation. This would in turn imply that the exposure effect would vanish if adjusted for the intermediate end point. We discuss the relative advantages of intervention and observational studies for the validation of intermediate end points. This validation strategy also may be applied to intermediate end points for adverse reproductive outcomes and chronic diseases other than cancer.

Biomarkers, Tumor↗

PubMed2001

Reliability and validity of the brief behavioral distress scale: a measure of children's distress during invasive medical procedures.

OBJECTIVE: To evaluate the reliability and validity of a new observational measure of children's procedure-related distress behaviors, the Brief Behavioral Distress Scale (BBDS), to provide clinicians with an efficient, economical alternative measure that does not depend on continuous interval coding. METHODS: Forty-eight randomly selected videotaped invasive medical procedures performed on children (ages 2 to 10 years) with chronic illness were coded with the BBDS and the Observation Scale of Behavioral Distress (OSBD). Reliability and validity analyses along with item analysis were conducted. RESULTS: Total distress scores of the BBDS were highly correlated with six of seven concurrent validity measures from multiple sources (i.e., OSBD, parent ratings, two nurse ratings, child self-report, and a physiological arousal measure, heart rate) (range r =.57-.76, p <.001-.0001). A robust association was found between the BBDS distress scores and OSBD total distress scores (r =.72, p <.0001). For two concurrent validity measures, the BBDS demonstrated stronger associations than did the OSBD. Interrater reliability was high for each BBDS distress behavior category. CONCLUSIONS: Based on the findings reported, the BBDS is a reliable and valid measure of children's procedure-related distress with functional utility in both research and clinical settings.

Adaptation, Psychological↗

PubMed2006

SNP500Cancer: a public resource for sequence validation, assay development, and frequency analysis for genetic variation in candidate genes.

The SNP500Cancer database provides sequence and genotype assay information for candidate SNPs useful in mapping complex diseases, such as cancer. The database is an integral component of the NCI Cancer Genome Anatomy Project (http://cgap.nci.nih.gov). SNP500Cancer reports sequence analysis of anonymized control DNA samples (n = 102 Coriell samples representing four self-described ethnic groups: African/African-American, Caucasian, Hispanic and Pacific Rim). The website is searchable by gene, chromosome, gene ontology pathway, dbSNP ID and SNP500Cancer SNP ID. As of October 2005, the database contains >13 400 SNPs, 9124 of which have been sequenced in the SNP500Cancer population. For each analysed SNP, gene location and >200 bp of surrounding annotated sequence (including nearby SNPs) are provided, with frequency information in total and per subpopulation as well as calculation of Hardy-Weinberg equilibrium for each subpopulation. The website provides the conditions for validated sequencing and genotyping assays, as well as genotype results for the 102 samples, in both viewable and downloadable formats. A subset of sequence validated SNPs with minor allele frequency >5% are entered into a high-throughput pipeline for genotyping analysis to determine concordance for the same 102 samples. In addition, the results of genotype analysis for select validated SNP assays (defined as 100% concordance between sequence analysis and genotype results) are posted for an additional 280 samples drawn from the Human Diversity Panel (HDP). SNP500Cancer provides an invaluable resource for investigators to select SNPs for analysis, design genotyping assays using validated sequence data, choose selected assays already validated on one or more genotyping platforms, and select reference standards for genotyping assays. The SNP500Cancer database is freely accessible via the web page at http://snp500cancer.nci.nih.gov.

Databases, Genetic↗

PubMed2005

Genome-wide selection of unique and valid oligonucleotides.

Functional genomics methods are used to investigate the huge amount of information contained in genomes. Numerous experimental methods rely on the use of oligo- or polynucleotides. Nucleotide strand hybridization forms the underlying principle for these methods. For all these techniques, the probes should be unique for analyzed genes. In addition to being unique for the studied genes, the probes should fulfill a large number of criteria to be usable and valid. The criteria include for example, avoidance of self-annealing, suitable melting temperature and nucleotide composition. We developed a method for searching unique and valid oligonucleotides or probes for genes so that there is not even a similar (approximate) occurrence in any other location of the whole genome. By using probe size 25, we analyzed 17 complete genomes representing a wide range of both prokaryotic and eukaryotic organisms. More than 92% of all the genes in the investigated genomes contained valid oligonucleotides. Extensive statistical tests were performed to characterize the properties of unique and valid oligonucleotides. Unique and valid oligonucleotides were relatively evenly distributed in genes except for the beginning and end, which were somewhat overrepresented. The flanking regions in eukaryotes were clearly underrepresented among suitable oligonucleotides. In addition to distributions within genes, the effects on codon and amino acid usage were also studied.

Amino Acids↗

PubMed2003

Reliability and validity of instruments measuring job satisfaction--a systematic review.

BACKGROUND: Although job satisfaction research has been carried out for decades, no recent overview of job satisfaction instruments and their quality is available. Aim The aim of this systematic review is to select job satisfaction instruments of adequate reliability and validity for use as evaluative tools in hospital environments. METHODS: Systematic literature searches were performed in the Medline and PsycInfo databases. First, the construct of job satisfaction was operationalized by generating work factors from both theoretical studies and meta-analyses or reviews of empirical studies on job satisfaction. Secondly, emphasis was placed on the internal consistency, construct validity and responsiveness of these instruments.Twenty-nine job satisfaction instruments were retrieved in total. RESULTS: Seven instruments met the defined reliability and validity criteria. Of the seven, the 'Measure of Job Satisfaction' had an adequate content validity. Only the 'Job in General Scale' provided data about 'responsiveness' to change. CONCLUSION: Few instruments have shown both high reliability and high validity, but little is known about their evaluative potential.

Humans↗