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Quality control validation in veterinary laboratories.

Quality control (QC) validation is used to determine: 1) whether statistical QC procedures are appropriate for detecting medically important errors; and 2) the equality of performance required by different laboratory tests. QC validation is well documented in the medical literature, but we are unaware of studies addressing its application, problems or unique differences in veterinary laboratories. We applied QC validation to automated hematology and biochemistry analyses in our laboratories, with goals of >/= 90% probability of error detection and </= 5% probability of false rejection. Analytical quality requirements in the form of total allowable error were defined using regulatory criteria for human proficiency testing; these were later modified based on clinician and pathologist feedback. Initial QC goals were not met for 14 of 49 (28.6%) analyte-control combinations. Subsequent modifications in methodology, analytical quality requirements and technician training achieved QC goals for all but one analyte. For this analyte (platelet count, low control), nonstatistical QC procedures were emphasized. QC validation was beneficial for clarifying statistical QC performance, and for assessing the need and justification for changes in methods and personnel training. The validation exercise allowed simplification of QC rules, enabled machine flagging of abnormal results, and decreased time and expense associated with QC recording, analysis, problem-solving and reruns. QC validation is recommended for all veterinary laboratories as a useful tool in total quality management.

Journal Article↗

On the validity of the Middlesex Hospital Questionnaire: a comparison of diagnostic self-ratings in psychiatric out-patients, general practice patients, and 'normals' based on the Hebrew version.

The short clinical diagnostic self-rating scale for psycho-neurotic patients (The Middlesex Hospital Questionnaire) was translated into everyday Hebrew and tested on 216 subjects for: (1) concurrent validity with clinical diagnoses; (2) discriminatory validity on a psychoneurotic gradient of psychiatric out-patients, general practice patients, and normal controls; (3) validity of subscales and discrete items using matrices of Spearman rank correlation coefficients; (4) construct validity using Guttman's smallest space analysis based on coefficients of similarity. The Hebrew MHQ was found to retain its validity and to be easily applicable in waiting-room situations. It is a useful method for generating and substantiating hypotheses on psychosomatic and psychosocial interrelationships. The MHQ seems to enable the expression of the 'neurotic load' of a general practice subpopulation as a centile on a scale, thereby corroborating previous epidemiological findings on the high prevalence of neurotic illness in general practice. There is reason to believe that the MHQ is a valid instrument for the analysis of symptom profiles of subjects involved in future drug trials.

Adolescent↗

Standardized ability tests and testing. Major issues and the validity of current criticisms of tests are discussed.

At the outset a distinction was made between criticisms directed at the validity of tests and criticisms not affected by the validity of the tests. It was noted further that all criticisms of tests must take into consideration the type of test and the use to which the test is put. Criticisms of the validity of tests involved the following issues: (i) tests may be unfair to certain groups and individuals, including the extremely gifted, the culturally disadvantaged, and those who lack experience in taking tests; (ii) tests are not perfect predictors of subsequent performance; (iii) tests may be used in overly rigid ways; (iv) tests may not measure inherent qualities of individuals; and (v) tests may contribute to their own predictive validity by serving as self-fulfilling prophecies. Criticisms that are more or less independent of test validity included the effects of tests on (i) thinking patterns of those tested frequently; (ii) school curricula; (iii) self-image, motivation, and aspirations; (iv) groups using tests as a criterion for selection or allocation, or both; and (v) privacy. Several concluding remarks are in order: 1) This paper has focused almost entirely on criticisms of tests. However, the positive value of standardized tests should not be ignored. Here we must keep in mind what possible alternative measures would be used if standardized tests were abandoned. 2) We must begin thinking about tests in a much broader perspective- one that includes consideration of the social effects of tests as well as their validity and reliability. 3) Finally, an effort should be made to develop rational and systematic policies on the use of tests with the culturally disadvantaged, the dissemination of test results, and the problem of invasion of privacy. Such policies can be formulated only if we are willing to take a long hard look at the role we want testing to play in the society. Standardized tests currently are a cornerstone in the edifice of stratification in American society. It is up to the social scientist to conduct research that will enable policy makers in education, business and industry, and government to determine in a consistent and rational way the ultimate shape of this edifice.

Achievement↗

Development and initial validation of an instrument to measure physicians' use of, knowledge about, and attitudes toward computers.

UNLABELLED: This paper describes details of four scales of a questionnaire-- "Computers in Medical Care"--measuring attributes of computer use, self-reported computer knowledge, computer feature demand, and computer optimism of academic physicians. The reliability (i.e., precision, or degree to which the scale's result is reproducible) and validity (i.e., accuracy, or degree to which the scale actually measures what it is supposed to measure) of each scale were examined by analysis of the responses of 771 full-time academic physicians across four departments at five academic medical centers in the United States. The objectives of this paper were to define the psychometric properties of the scales as the basis for a future demonstration study and, pending the results of further validity studies, to provide the questionnaire and scales to the medical informatics community as a tool for measuring the attitudes of health care providers. METHODOLOGY: The dimensionality of each scale and degree of association of each item with the attribute of interest were determined by principal components factor analysis with orthogonal varimax rotation. Weakly associated items (factor loading < .40) were deleted. The reliability of each resultant scale was computed using Cronbach's alpha coefficient. Content validity was addressed during scale construction; construct validity was examined through factor analysis and by correlational analyses. RESULTS: Attributes of computer use, computer knowledge, and computer optimism were unidimensional, with the corresponding scales having reliabilities of .79, .91, and .86, respectively. The computer-feature demand attribute differentiated into two dimensions: the first reflecting demand for high-level functionality with reliability of .81 and the second demand for usability with reliability of .69. There were significant positive correlations between computer use, computer knowledge, and computer optimism scale scores and respondents' hands-on computer use, computer training, and self-reported computer sophistication. In addition, items posited on the computer knowledge scale to be more difficult generated significantly lower scores. CONCLUSION: The four scales of the questionnaire appear to measure with adequate reliability five attributes of academic physicians' attitudes toward computers in medical care: computer use, self-reported computer knowledge, demand for computer functionality, demand for computer usability, and computer optimism. Results of initial validity studies are positive, but further validation of the scales is needed. The URL of a downloadable HTML copy of the questionnaire is provided.

Attitude of Health Personnel↗

Use of tissue microarray for interlaboratory validation of HER2 immunocytochemical and FISH testing.

AIMS: To evaluate the use of tissue microarray (TMA) technology as a validation tool for HER2 testing by both immunocytochemistry (ICC) and fluorescence in situ hybridisation (FISH) in the diagnostic setting. METHODS: TMA constructs from 57 cases of breast cancer were evaluated for HER2 (by ICC and FISH) by two centres. The results were compared. RESULTS: There was a high level of concordance for both ICC and FISH. In five "discrepant" cases only three would have had a potential impact on patient management. CONCLUSIONS: Validation of HER2 analysis in the clinical setting by ICC and FISH is essential. The use of TMAs provides for an economy of scale and would be practical in the setting of interlaboratory and intralaboratory validation. It is suggested that routine HER2 ICC and FISH should continue to be performed in laboratories on whole sections. Following this, TMAs would be constructed for all cases of breast cancer. ICC and FISH would be performed on these to validate the results. The TMAs would be available for circulation to other centres for validation purposes. The standardisation of testing between centres, the potential difficulty of minimum case numbers, and the workload issues surrounding validation would all be facilitated by this approach.

Antibodies, Monoclonal↗

Development and validation of a core outcome measure for palliative care: the palliative care outcome scale. Palliative Care Core Audit Project Advisory Group.

OBJECTIVES: To develop an outcome measure for patients with advanced cancer and their families which would cover more than either physical symptoms or quality of life related questions. To validate the measure in various specialist and non-specialist palliative care settings throughout the UK. DESIGN: A systematic literature review of measures appropriate for use in palliative care settings was conducted. In conjunction with a multidisciplinary project advisory group, questions were chosen for inclusion into the scale based on whether they measured aspects of physical, psychological, or spiritual domains pertinent to palliative care, and whether similar items had shown to be valid as part of another measure. A staff completed version was developed to facilitate data collection on all patients throughout their care, and a patient completed version was designed to enable the patient to contribute to the assessment of their outcomes when possible. A full validation study was conducted to evaluate construct validity, internal consistency, responsiveness to change over time, and test-retest reliability. Assessments were timed. SETTING: Eight centres in England and Scotland providing palliative care, including inpatient care, outpatient care, day care, home care, and primary care. PATIENTS: A total of 450 patients entered care during the study period. Staff collected data routinely on patients in care long enough to be assessed (n = 337). Of these, 262 were eligible for patient participation; 148 (33%) went on to complete a questionnaire. MAIN MEASURES: The Palliative Care Outcome Scale (POS), the European Organisation for Research on Cancer Treatment, and the Support Team Assessment Schedule. RESULTS: The POS consists of two almost identical measures, one of which is completed by staff, the other by patients. Agreement between staff and patient ratings was found to be acceptable for eight out of 10 items at the first assessment. The measure demonstrated construct validity (Spearman rho = 0.43 to 0.80). Test/re-test reliability was acceptable for seven items. Internal consistency was good (Cronbach's alpha = 0.65 (patients), 0.70 (staff)). Change over time was shown, but did not reach statistical significance. The questionnaire did not take more than 10 minutes to complete by staff or patients. CONCLUSION: The POS has acceptable validity and reliability. It can be used to assess prospectively palliative care for patients with advanced cancer.

England↗

[Selection of risk and diagnosis in diabetic polyneuropathy. Validation of method of new systems].

INTRODUCTION: In a previous study we developed a specific algorithm, the polyneuropathy selection method (PSM) with 4 parameters (age, HDL-C, HbA1c, and retinopathy), to select patients at risk of diabetic polyneuropathy (DPN). We also developed a simplified method for DPN diagnosis: outpatient polyneuropathy diagnosis (OPD), with 4 variables (symptoms and 3 objective tests). OBJECTIVES: To confirm the validity of conventional tests for DPN diagnosis; to validate the discriminatory power of the PSM and the diagnostic value of OPD by evaluating their relationship to electrodiagnosis studies and objective clinical neurological assessment; and to evaluate the correlation of DPN and pro-inflammatory status. DESIGN: Cross-sectional, crossed association for PSM validation. Paired samples for OPD validation. SETTING: Primary care in 3 counties. PARTICIPANTS: Random sample of 75 subjects from the type-2 diabetes census for PSM evaluation. Thirty DPN patients and 30 non-DPN patients (from 2 DM2 sub-groups in our earlier study) for OPD evaluation. METHODS: The gold standard for DPN diagnosis will be studied by means of a clinical neurological study (symptoms, physical examination, and sensitivity tests) and electrodiagnosis studies (sensitivity and motor EMG). Risks of neuropathy, macroangiopathy and pro-inflammatory status (PCR, TNF soluble fraction and total TGF-beta1) will be studied in every subject. EXPECTED RESULTS: Electrodiagnosis studies should confirm the validity of conventional tests for DPN diagnosis. PSM and OPD will be valid methods for selecting patients at risk and diagnosing DPN. There will be a significant relationship between DPN and pro-inflammatory tests.

Algorithms↗

Validity of different linguistic versions of the Alzheimer's Disease Assessment Scale in an international multicentre Alzheimer's disease trial.

Owing to the involvement of Italian Centres in a multicentre, German-Italian therapeutical trial with Alzheimer's dementia patients, to be assessed with the Alzheimer's Disease Assessment Scale (ADAS), it was decided that the Italian centres would use an Italian version of the scale, derived from that used by the German centres. However, the lists of words for exploring verbal memory are not merely translated from the German version, but are composed of selective Italian words chosen according to linguistic criteria. This Italian version was validated following the same procedure adopted for validating the German version. We submitted this Italian version to an interrater reliability, test-retest reliability, concurrent validity, internal consistency and sensitivity evaluation, using demented patients. Based on the results of these tests this Italian version of the ADAS proved valid and reliable. Moreover, the results were strikingly comparable to those from the validation of the German version. Our work supports the validity, reliability and transnational comparability of national versions of the ADAS constructed following definite linguistic criteria.

Adult↗

On the validity of the Beck Depression Inventory. A review.

The present review discusses validity aspects of the Beck Depression Inventory (BDI) on the basis of meta-analyses of studies on the psychometric properties. Shortcomings of the BDI are its high item difficulty, lack of representative norms, and thus doubtful objectivity of interpretation, controversial factorial validity, instability of scores over short time intervals (over the course of 1 day), and poor discriminant validity against anxiety. Advantages of the inventory are its high internal consistency, high content validity, validity in differentiating between depressed and nondepressed subjects, sensitivity to change, and international propagation. The present paper outlines agreements and contradictions between the various studies on the BDI and discusses the potential factors (composition of the subject sample, statistical procedures, point in time of measurement) accounting for the variance in their results. The Beck Depression Inventory (BDI) is world-wide among the most used self-rating scales for measuring depression. Since the test construction in 1961, the test has been employed in numerous (more than 2,000) empirical studies. The present review will only consider those investigations which are primarily concerned with the validity or the psychometric properties of the BDI. Since most studies are oriented along the criteria of the classical test theory, our review will discuss to what extent the BDI meets these criteria.

Depressive Disorder↗

Comparative reproducibility and validity of systems for assessing cardiovascular functional class: advantages of a new specific activity scale.

Reproducibility and validity are prerequisites for a useful clinical scale. We therefore prospectively tested the reproducibility and validity of the New York Heart Association criteria and the Canadian Cardiovascular Society criteria for the assessment of cardiac functional class and compared these criteria with a new Specific Activity Scale based on the metabolic costs of specific activities. The New York Heart Association estimates made by two physicians had a reproducibility of only 56%, and only 51% of the estimates agreed with treadmill exercise performance. Functional estimates based on the Canadian Cardiovascular Society criteria were significantly more reproducible (73%), but not significantly more valid. The Specific Activity Scale was as reproducible as the Canadian Cardiovascular Society criteria, and its 68% validity was significantly higher than the validities of the other systems. The easily administered Specific Activity Scale was equally reproducible and valid when used by a nonphysician. It was especially better than the other systems for the evaluation of true class II patients and was significantly less likely to underestimate treadmill performance. Although no set of questions can perfectly predict exercise tolerance, the Specific Activity Scale deserves wider prospective testing.

Canada↗

Is the EuroQol a valid measure of health-related quality of life after stroke?

BACKGROUND AND PURPOSE: The EuroQol measures aspects of quality of life that are highly relevant to stroke patients. It is short and simple and many stroke patients can complete the form without help. However, its validity has not been adequately assessed after stroke. We therefore assessed its concurrent and discriminant validity in a group of prospectively studied stroke survivors. METHODS: We assessed the validity of the EuroQol in a series of 152 patients with stroke who were all visited by a study nurse. The nurse gave the patients the EuroQol, the Frenchay Activities Index, a visual analogue pain scale, and the Hospital Anxiety and Depression Scale in the form of questionnaires to be self-completed where possible. The nurse interviewed the patient directly to assess disability using the Office of Population Censuses and Surveys Disability scale and Barthel Index. RESULTS: The nurse assessed 152 patients; of these 92 were able to complete the EuroQol without help, the remaining 60 could only be assessed by interview. The EuroQol had reasonable concurrent validity; median scores on the relevant standard instruments varied significantly (and in the appropriate direction) for groups defined by their response to the relevant EuroQol domain. The EuroQol had reasonable discriminant validity since the responses enabled separation between patients with differing stroke syndromes and stroke severities. Accuracy for predicting outcome after stroke was good for both self-completed and interview-completed questionnaires. CONCLUSIONS: The EuroQol appears to have acceptable concurrent and discriminant validity for the measurement of health-related quality of life after stroke. It may be administered by either a questionnaire for self-completion in patients with mild to moderate stroke or by interview in patients with significant motor deficits.

Aged↗

Distinguishing between the validity and utility of psychiatric diagnoses.

OBJECTIVE: The meaning of the terms "validity" and "utility" as they apply to psychiatric diagnoses is examined. METHOD: The authors discuss the concepts of validity, utility, and disease; review assumptions that have been made about mental disorders as disease entities; and examine the evidence that mental disorders are separated from one another and from normality by natural boundaries (zones of rarity). RESULTS: Despite historical and recent assumptions to the contrary, there is little evidence that most currently recognized mental disorders are separated by natural boundaries. Researchers are increasingly assuming that variation in symptoms is continuous and are therefore questioning the validity of contemporary classifications. CONCLUSIONS: It is important to distinguish between validity and utility in considering psychiatric diagnoses. Diagnostic categories defined by their syndromes should be regarded as valid only if they have been shown to be discrete entities with natural boundaries that separate them from other disorders. Although most diagnostic concepts have not been shown to be valid in this sense, many possess high utility by virtue of the information about outcome, treatment response, and etiology that they convey. They are therefore invaluable working concepts for clinicians.

Humans↗

Validation assessment of the Chinese-version Chronic Ear Survey: a comparison between data from English and Chinese versions.

The Chronic Ear Survey (CES) is a valid, disease-specific measure for the evaluation of health status and treatment effectiveness for adults with chronic suppurative otitis media (CSOM). This study compares the validation properties of the English and Chinese versions of the CES. The CES was translated into Mandarin Chinese by means of a parallel model. The Chinese version of the CES (CCES) was administered to 103 patients in a prospective manner, then was validated according to established criteria for reliability, validity, and longitudinal sensitivity. The CCES demonstrated good test-retest reliability and internal consistency (Cronbach's a = 0.81). The CCES significantly correlated with the Mandarin Chinese (Taiwan) version of the generic 36-Item Short-Form Health Survey (TSF-36). The standardized response mean for the CCES total score was 2.1, indicating excellent sensitivity to clinical change. This validation study demonstrated that the performance characteristics of the CCES were equivalent to those of the English-version CES. The CCES is a valid tool for evaluation of adults with CSOM among the Chinese-speaking population.

Activities of Daily Living↗

An Arabic validation of a depression inventory.

The present study describes an Arabic cross-cultural validation of the Beck Depression Inventory. An Arab sample of 53 cases was subjected to the original validation procedures which involved a preliminary exercise and a translation from English to Arabic. Acceptable equivalent meanings of Beck's depth-of-depression criteria were established by the Arab clinicians so that independent and valid clinical ratings could be made. Statistical analyses of the internal consistency and stability of the Arabic-BDI indicated a high degree of reliability. Correlations between Arabic-BDI scores and Arab clinicians' ratings indicated a high degree of validity. The results of the cross-cultural validation study agree favorably with those of the original American validation. Although the Arabic inventory makes possible an assessment of the level and intensity of a reactive type depression suffered by Saudi Arab psychiatric outpatients living in the Eastern Province, it must be adapted dialectically for other Arab-speaking regions.

Adolescent↗

The validity of subscores for a credentialing test.

Subscores resulting from the administration of high-stakes tests to candidates for credentials in the health professions are desirable for two reasons. First, failing candidates want a profile of performance to plan future remedial studies. Second, training institutions want a profile of performance for their graduates to better evaluate their training. The validity of the interpretation or use of subscores depends on a summative judgment based on a combination of reasoning and empirical analyses, known as validation. We describe this reasoning process and show that with a large credentialing test the validity of any subscore interpretation or use can and should be studied systematically. Validity evidence should be established to support the interpretation and use of subscores that we intend to report. Some principles arise in this study related to the validity of subscores, and some procedures are proposed to help testing program personnel better validate the use of subscores.

Analysis of Variance↗

Importance of expert judgment in content-related validity evidence.

The unified conceptualization of validity with regard to content-related evidence has been expressed succinctly by the authors of the Standards for Educational and Psychological Testing (AERA et al., 1985): Content-related evidence of validity is a central concern during [instrument] development, whether such development occurs in a research setting, in a publishing house, or in the context of professional practice. Expert professional judgment should play an integral part in developing the definition of what is to be measured, such as describing the universe of content, generating or selecting the content sample, and specifying the item format and scoring system. Thus, inferences about content are linked to [instrument] construction as well as to establishing evidence of validity after [an instrument] has been developed and chosen for use. (p. 11) This article has demonstrated the process of collecting content-related validity evidence in terms of the specific requirements of the Standards. Five standards were identified and interpreted according to the initial stages of instrument construction: domain specification, item development, and item, subscale, and scale content validation. The role of expert judgment during these stages and the variety of evidence that can be gathered were described. For most instruments, the review process would necessitate two meetings of 1 to 2 hours each to review the domain specifications and another two meetings to determine the match between the items and the specifications. The importance of these 8 hours or whatever additional time is needed to obtain the validity evidence was emphasized. Finally, an application of the Standards was provided to illustrate step-by-step how the judgmental review process can be planned and executed.

Acquired Immunodeficiency Syndrome↗

Are reliability, reproducibility and validity the correct terms to assess the correctness of dietary studies?

Nutritional studies often use the terms reliability, reproducibility and validity to indicate the correctness of the study. These terms do not appear to have a universal meaning to all researchers. The components of a dietary study are the input, the data collection instrument and the compiled data. Frequently the data collection questionnaire/tool/instrument is tested for reliability, reproducibility or validity. The data collection questionnaire/tool/instrument is simply a structure, a vehicle for gathering data. An argument is presented that demonstrates the reasons that such a structure cannot be tested for reliability, reproducibility or validity. The logical approach to the use of the terms reliability, reproducibility and validity is presented. Reliability refers to the input component of the study, reproducibility may or may not lead to strengthening the study and validity refers to the truthfulness of the database generated. Validity must be derived from reliable and reproducible data.

Diet Surveys↗

Development and validation of the quality of life outcome measure (questionnaire) for chronic anterior cruciate ligament deficiency.

A patient-based, subjective outcome measure for chronic anterior cruciate ligament deficiency was developed, pretested, and validated. The development of the outcome measure was completed in four stages: 1) item generation (167 items), 2) item reduction (by surveying 79 patients), 3) questionnaire formation and pretesting (20 patients), and 4) reliability, responsiveness, and validity assessment (100 patients). This disease-specific quality of life measure is a 32-item questionnaire using a 100-mm visual analog scale response format. Face validity was derived from extensive direct patient input. Content validity was determined by consensus among 20 knee surgeons. There was no significant difference on test-retest reliability, with an overall average error of 6%. The outcome measure demonstrated responsiveness to clinical change correctly in 21 of 25 patients (84%). Construct validity was shown by the ability of the questionnaire to measure the full spectrum of disease; scores ranged from 8 to 99 out of a maximum score of 100. The questionnaire was able to distinguish patients who went on to have surgery (average score, 31) from those who would be treated nonoperatively (average score, 79). The quality of life outcome measure for chronic anterior cruciate ligament deficiency is the first subjective knee scale of its kind to be validated to measure quality of life in patients with chronic anterior cruciate ligament deficiency.

Adolescent↗