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PubMedDate not supplied

Validation of models for predicting the use of health technologies.

Validation must be carried out before a model can be used confidently as a tool of managerial decision making in health care. The authors describe a bootstrap approach to validating models for predicting the utilization of four technologies used in neonatal care: measurement of blood gases (gasometry), the oxygen hood, continuous positive airway pressure (CPAP), and mechanical ventilation. These models were fitted by stepwise multiple linear regression from 20 prognostic covariates of 193 neonates. One hundred bootstrap samples were generated to validate the choices of covariates in the models based on their frequencies of selection. This approach validated the models for the oxygen hood and CPAP. The regression coefficients and standard deviations for the CPAP and oxygen hood models were estimated using 200 additional bootstrap samples. A close agreement between stepwise and bootstrap estimates was observed for both models. These results suggest that bootstrap can be useful for validating models for predicting the utilization of health technologies.

Blood Gas Analysis↗

PubMed1979

The research diagnostic criteria: historical background, development, validity, and reliability.

This article reviews the theoretical papers and research studies concerning the Research Diagnostic Criteria (RDC), a research tool used to group psychiatric sugjects into homogenous diagnostic groups. The RDC contains specified inclusion and exclusion criteria for 25 diagnostic categories. The contributions made by the Feighner and Spitzer groups in the field of diagnostic reliability and validity are briefly outlined. The development of the RDC and studies regarding its reliability and validity are presented and discussed. A review of the reliability studies, which basically employed an interrater design, indicated that the RDC is a relatively reliable diagnostic tool, obtaining interrater kappa coefficients which are consistently higher than those obtained, for similar categories, in studies using other diagnostic systems such as the DSM-II. Very few studies, however, directly investigated the validity of the RDC. Its assumed validity is dependent on the findings from studies which used similar diagnostic criteria. It was suggested that more studies would be required to establish the validity of the RDC. Several limitations of the RDC were pointed out. Included among these were: its use of an exclusion method to determine diagnostic criteria, the difficulty and great amount of time required for its use, and the fact that it has so far been used only with adult inpatients. Despite its limitations, it was concluded that the RDC remains one of the best tools available to a researcher who wishes to group psychiatric patients into homogenous groups, and that the clinician could advantageously use it in his clinical practice.

Humans↗

PubMed1990

Validation of the alexithymia construct: a measurement-based approach.

Alexithymia is a hypothetical personality construct that has been associated with a variety of medical and psychiatric disorders. This article reviews a program of research evaluating the validity of the construct using a measurement-based, construct validation approach. For this purpose the Toronto Alexithymia Scale (TAS) was developed. In a series of studies the TAS demonstrated internal consistency, good test-retest reliability, and a stable factor structure theoretically congruent with the alexithymia construct. In separate tests of construct validity, the TAS correlated in a theoretically meaningful fashion with measures of other constructs. Criterion validity was supported by a study in which the TAS was able to discriminate between behavioural medicine outpatients designated as alexithymic and those designated as nonalexithymic on the basis of objectively rated structured interviews. In a normal adult sample, TAS scores were not related to sociodemographic variables or intelligence. These results provide considerable empirical support for the validity of the alexithymia construct. In addition, the TAS appears to be a psychometrically sound measure of alexithymia that may prove useful in testing the construct with psychiatric and medical patient populations.

Adolescent↗

PubMed2004

Pragmatic and internal validity issues in sampling in caregiver studies: a comparison of population-based, registry-based, and ancillary studies.

OBJECTIVES: Studies of caregivers illustrate a classic sampling dilemma: maximizing recruitment without compromising study validity. Because caregivers are defined in relation to a care recipient, sampling methods are often determined by pragmatic decisions such as access, efficiency, and costs. However, overlooking validity may result in selection bias, misclassification of caregiver status, and the confounding of results. Validity and pragmatic concerns were compared in four caregiver studies that used different sampling frames: community based, Alzheimer's disease registry, and ancillary studies to existing epidemiologic studies. METHODS: Systematic comparison of validity and of pragmatic aspects of sampling frames, recruitment methods, and participation rates, with attention to caregiver identification, inclusion criteria, and sample restriction. RESULTS: All studies used task-based inclusion criteria. Caregiver participation rates ranged from 81% to 96%, with higher rates in community-based and registry-based studies than in ancillary studies. The latter studies benefited from unbiased selection of noncaregivers. DISCUSSION: Regardless of sampling frame, standard task-based inclusion criteria to define caregivers may enhance validity.

Aged↗

PubMed2001

Validity in qualitative research.

Much contemporary dialogue has centered on the difficulty of establishing validity criteria in qualitative research. Developing validity standards in qualitative research is challenging because of the necessity to incorporate rigor and subjectivity as well as creativity into the scientific process. This article explores the extant issues related to the science and art of qualitative research and proposes a synthesis of contemporary viewpoints. A distinction between primary and secondary validity criteria in qualitative research is made with credibility, authenticity, criticality, and integrity identified as primary validity criteria and explicitness, vividness, creativity, thoroughness, congruence, and sensitivity identified as secondary validity criteria.

Evaluation Studies as Topic↗

PubMed1988

Record linkage studies for postmarketing drug surveillance: data quality and validity considerations.

Large automated databases are the source of information for many record linkage studies, including postmarketing drug surveillance. Despite this reliance on prerecorded data, there have been few attempts to assess data quality and validity. This article presents some of the basic data quality and validity issues in applying record linkage methods to postmarketing surveillance. Studies based on prerecorded data, as in most record linkage studies, have all the inherent problems of the data from which they are derived. Sources of threats to the validity of record linkage studies include the completeness of data, the ability to accurately identify and follow the records of individuals through time and place, and the validity of data. This article also describes techniques for evaluating data quality and validity. Postmarketing surveillance could benefit from more attention to identifying and solving the problems associated with record linkage studies.

Database Management Systems↗

PubMed2004

A meta-analysis of outcome rating scales in foot and ankle surgery: is there a valid, reliable, and responsive system?

BACKGROUND: Rating scales that are valid, reliable, and responsive communicate the severity of a functional problem, facilitate the accurate study of treatment modalities, and provide a common language for those involved in research. The purpose of this study was to determine which outcome rating scales are currently used in the foot and ankle literature and to identify rating scales with proven reliability, validity, and responsiveness. METHOD: A meta-analysis of the foot and ankle literature from 1990 to 2001 was done. All referenced rating scales were reviewed to determine if any had proven to be reliable, valid, or responsive. RESULTS: Forty-nine different rating scales were identified. The most frequently referenced scales were the subscales of the American Orthopaedic Foot and Ankle Society (AOFAS). No rating scale was identified that demonstrated reliability, validity, and responsiveness in patients with a variety of foot and ankle conditions. CONCLUSIONS: The development of a reliable, valid, and responsive rating scale would have value not only in assessing patient outcomes but also in reporting the results of clinical studies in foot and ankle surgery.

Ankle↗

PubMed1999

Performance of the Personality Inventory for Youth validity scales.

Response sets as well as cognitive and academic deficits compromise the validity of child and adolescent self-report of emotional adjustment. Three studies using clinical and asymptomatic samples of 4th to 12th grade students detail applications of the four validity scales of the Personality Inventory for Youth (PIY), namely, (a) Validity (VAL) a scale of six highly improbable statements, (b) Inconsistency (INC) consisting of pairs of highly correlated statements, (c) Dissimulation (FB) constructed of statements that were infrequent and characteristic of intentional distortion, and (d) Defensiveness (DEF) an extension of the Lie scale of the parent-report Personality Inventory for Children. The effects of minimizing, malingering, and random response sets on the PIY validity scales are reported. The importance of such validity scales derived from child and adolescent response is discussed.

Adolescent↗

PubMed2003

Virus-based expression systems facilitate rapid target in vivo functionality validation and high-throughput screening.

Target validation is one of rate-limiting steps in the modern drug discovery. The authors developed a strategy of combining adenovirus-mediated gene transfer for efficient target functionality validation, both in vivo and in vitro, with baculovirus expression to produce sufficient quantities of protein for high-throughput screening (HTS). The incorporation of green fluorescent protein (GFP) in the adenovirus vectors accelerates recombinant adenovirus plaque purification, whereas the use of epitope and affinity tags facilitates the identification and purification of recombinant protein. In this generalized scheme, the flexible modular design of viral vectors facilitates the transition between target validation and HTS. In the example presented, functional target validation in vivo was achieved by overexpressing the target gene in cell-based models and in the mouse cortex following adenovirus-mediated gene delivery. In this context, target overexpression resulted in the accumulation of a disease-related biomarker both in vitro and in vivo. A baculovirus-based expressional system was then generated to produce enough target protein for HTS. Thus, the use of these viral expression systems represents a generalized method for rapid target functionality validation and HTS assay development, which could be applied to numerous target candidates being elucidated in gene discovery programs.

Adenoviridae↗

PubMed2001

Disease specific quality of life instruments in multiple sclerosis: validation of the Hamburg Quality of Life Questionnaire in Multiple Sclerosis (HAQUAMS).

Quality of life (QoL) is discussed as an additional outcome measure in multiple sclerosis (MS). However, few questionnaires assessing disease specific QoL in MS have been published. On the basis of the literature and interviews with clinicians and MS patients, we have developed a disease specific QoL instrument and validated it in a broad range of patients with MS. In this study, a heterogeneous sample of n = 237 MS patients completed the newly developed Hamburg Quality of Life Questionnaire in Multiple Sclerosis (HAQUAMS, in German language) and a battery of already validated questionnaires. They further underwent neurological scoring and objective tests. By these means, we investigated its validity, appropriateness, internal consistency, and retest reliability. Internal consistency and retest coefficients were high and satisfied psychometric standards. Convergent and discriminant validity was supported by direction, magnitude and pattern of correlations with other health measures. HAQUAMS subscales and its total score distinguished between patient groups of varied disease severity, cognitive impairment, and affective symptomatology. No floor or ceiling effects were found in either of the HAQUAMS subscales. The HAQUAMS is a reliable, valid and appropriate instrument for QoL assessment in multiple sclerosis. Data of responsiveness are currently being obtained.

Adult↗

PubMed1997

Reliability and validity assessments of measures of social networks, social support and control--results from the Malmö Shoulder and Neck Study.

The reliability and validity of methods to assess social networks, social support and control were investigated in a population of 12,009 females and males born between 1926 and 1945 (the "Malmö Shoulder and Neck Study"). This study demonstrated an overall reliability with kappa coefficients between 0.70 and 0.47, but the reliability was more varying among females and lower in the youngest age group. The analysis of the construct validity indicated that the different indices measure different aspects of the psychosocial environment, but both theoretical and methodological problems were identified, when the validity of multidimensional concepts are to be determined. The validity of such indices can best be judged by combining quantitative and qualitative methods. Potential validity problems must be kept in mind when these indices are used in epidemiological research. The results from the reliability analysis call for repeated assessments and the sample size must be adjusted vis-a-vis the reliability.

Aged↗

PubMed1995

Validation of the surveillance system for new cases of tuberculosis in a province of northern Italy. Varese Tuberculosis Study Group.

In Italy tuberculosis (TB) surveillance is hampered by several problems (inconsistency of data and underreporting). A tuberculosis surveillance system was established in Varese Province (VSS) in 1992. The aim of the present study was, using VSS, to estimate: 1) coverage and validity of data collected by the national Compulsory Surveillance System (CSS); 2) validity of diagnosis and risk factors for tuberculosis; 3) tuberculosis incidence. A specifically designed form, including the same items as the CSS form and 10 more questions on risk factors and diagnostic issue, was completed in all the existing health facilities in the province for each new tuberculosis case diagnosed, collected by the study co-ordinator during monthly supervision after a review of clinical records, and stored in a database at the co-ordinating centre. Routine notifications collected at national level by CSS for the province were nominally linked with VSS data. To evaluate coverage and data validity, a comparison was made between VSS and CSS data after removal of duplicates. Quality of data, risk factors and incidence were evaluated on VSS data (gold standard). CSS coverage was 63% with a significant underreporting of extrapulmonary cases. Within CSS, 20% of data were missing (particularly diagnostic information: 42-72%). According to VSS, smear was performed on 88% of cases and culture on 66%. Half of the cases had no risk factors. The overall incidence of tuberculosis in Varese Province was 15 per 100,000. We estimated the coverage and validity of the data collected by CSS, validity of diagnosis, risk factors for and incidence of tuberculosis and proposed several suggestions to improve CSS nationwide.

Adolescent↗

PubMed2006

The Shoulder Pain and Disability Index demonstrates factor, construct and longitudinal validity.

BACKGROUND: The Shoulder Pain and Disability Index (SPADI) is a self-report measure developed to evaluate patients with shoulder pathology. While some validation has been conducted, broader analyses are indicated. This study determined aspects of cross-sectional and longitudinal validity of the SPADI. METHODS: Community volunteers (n = 129) who self-identified as having shoulder pain were enrolled. Patients were examined by a physical therapist using a standardized assessment process to insure that their pain was musculoskeletal in nature. This included examination of pain reported during active and passive shoulder motion as reported on a visual analogue pain scale. Patients completed the SPADI, the Coping Strategies Questionnaire (CSQ) and the Sickness Impact Profile (SIP) at a baseline assessment and again 3 and 6 months later. Factor analysis with varimax rotation was used to assess subscale structure. Expectations regarding convergent and divergent subscales of CSQ and SIP were determined a priori and analysed using Pearson correlations. Constructed hypotheses that patients with a specific diagnosis or on pain medication would demonstrate higher SPADI scores were tested. Correlations between the observed changes recorded across different instruments were used to assess longitudinal validity. RESULTS: The internal consistencies of the SPADI subscales were high (alpha > 0.92). Factor analysis with varimax rotation indicated that the majority of items fell into 2 factors that represent pain and disability. Two difficult functional items tended to align with pain items. Higher pain and disability was correlated to passive or negative coping strategies, i.e., praying/hoping, catastrophizing on the CSQ. The correlations between subscales of the SPADI and SIP were low with divergent subscales and low to moderate with convergent subscales. Correlations, r > 0.60, were observed between the SPADI and pain reported on a VAS pain scale during active and passive movement. The two constructed validity hypotheses (on diagnosis and use of pain medications) were both supported (p < 0.01). The SPADI demonstrated significant changes over time, but these were poorly correlated to the SIP or CSQ suggesting that these scales measure different parameters. CONCLUSION: The SPADI is a valid measure to assess pain and disability in community-based patients reporting shoulder pain due to musculoskeletal pathology.

Adaptation, Psychological↗

PubMed2003

A biomechanical investigation into the validity of the modified Ashworth Scale as a measure of elbow spasticity.

OBJECTIVE: To investigate the criterion validity of the modified Ashworth Scale. POPULATION: Volunteers from a stroke population admitted to a district general hospital stroke unit diagnosed with a first ever stroke less than 26 weeks previously. OUTCOME MEASURES: Resistance to passive movement about the elbow was simultaneously quantified (biomechanically) and graded (modified Ashworth Scale). Passive range of movement and peak instantaneous velocity during passive movement were also measured. ANALYSIS: Criterion validity was investigated as convergent construct validity (using the Spearman's correlation coefficient) and concurrent validity (using analysis of variance). RESULTS: One hundred measurements were taken on 63 subjects. Correlation between the modified Ashworth Scale and resistance to passive movement was 0.511. Resistance to passive movement and velocity showed significant differences between the modified Ashworth score of '0' and a modified Ashworth score greater than '0' (p < 0.01). There were no significant differences between MAS '1', '1+' and '2'. Resistance to passive movement in the impaired arm was significantly higher than in the nonimpaired arm (p < 0.01). CONCLUSION: The modified Ashworth Scale does not provide a valid measure of spasticity at lower grades but it may provide a measure of resistance to passive movement.

Biomechanical Phenomena↗

PubMed2003

The Mobility Scale for Acute Stroke Patients: concurrent validity.

OBJECTIVE: A new scale, the Mobility Scale for Acute Stroke Patients (MSAS), was developed to specifically discriminate between the lower levels of mobility found in acute stroke patients in the first two weeks post onset. The aim of this study was to investigate the concurrent validity of this new scale with other established scales. MAIN OUTCOME MEASURES: Concurrent validity was assessed with respect to four other well-validated measures: Motor Assessment Scale (MAS), Functional Ambulation Classification system (FAC), Functional Independence Measure (FIM), and Barthel Index (BI). The measures selected for comparison contained items similar to those in the MSAS. SUBJECTS: From a total of 539 patients who were admitted over a two-year period with a primary diagnosis of stroke, 106 satisfied the criteria for inclusion in this study. RESULTS: The MSAS was found to have a high level of concurrent validity (r > 0.80) when the total score was correlated with the total scores of the MAS, FAC, FIM (mobility and ADL) and BI. A high level of association was found between the nonbed mobility items (sit to stand, stand and walk) of the MSAS and the mobility items (toileting, transfers, walk and stairs) of the FIM and BI. There was a weaker association between the MSAS items and the ADL items (activities of daily living) of the BI and FIM. CONCLUSION: A new scale designed specifically for acute stroke patients was found to have a high degree of concurrent validity when compared with four other scales containing similar items.

Activities of Daily Living↗

PubMed2002

A Chinese version of the Rheumatology Attitudes Index is a valid and reliable measure of learned helplessness in patients with SLE.

Despite the prognostic importance of learned helplessness (LH) in rheumatic diseases, there are no validated measures of LH in Chinese or other Asian languages. We therefore assessed the validity of a Chinese translation of the Rheumatology Attitudes Index (CRAI; a widely used measure of LH) and its Helplessness (CHS) and Internality (CIS) subscales in patients with SLE. Chinese-speaking SLE patients (n = 69) completed identical, self-administered questionnaires containing the CRAI and assessing demographic/socio-economic variables twice within 2 weeks. SLE activity, damage and quality of life were assessed using the BILAG, SLICC/ACR Damage Index and SF-36 respectively. Scale psychometric properties were assessed through Cronbach's alpha, intra-class correlations, quantifying test-retest differences, factor analysis and known-groups construct validity. Internal consistency and reliability were acceptable, with Cronbach's alpha for the CHS, CIS and CRAI being 0.70, 0.69 and 0.74, respectively. Mean differences in test-retest scores spanned 1.6-2.4% of possible scale ranges and intra class correlations ranged from 0.72 to 0.88. Factor analysis identified two major factors corresponding to the CHS and CIS subscales of the CRAI. Eight of 10 a priori hypotheses relating the CRAI and CHS to demographic, disease and quality of life variables were confirmed, supporting the construct validity of these scales. The CRAI and its helplessness subscale are valid and reliable measures of learned helplessness in Chinese-speaking SLE patients.

Adolescent↗

PubMed1999

Validity and reliability of the Health of the Nation Outcome Scales in psychiatric patients in the community.

BACKGROUND: The Health of the Nation Outcome Scales (HoNOS) have been developed for assessing the effectiveness of mental health services. AIMS: To investigate the validity and reliability of the HoNOS in patients in contact with mental health services. METHOD: Subjects (age range 19-64) came from day hospitals, acute in-patient units and out-patient clinics in general practice. We obtained the opinions of experienced professionals, advocacy groups and patient groups to evaluate consensual and content validity. RESULTS: One hundred patients were assessed using the package of rating scales. Interrater and test-retest reliability were good for some items and poor for others. The HoNOS had good criterion validity: acute in-patients had higher scores than day patients and out-patients. HoNOS also had good concurrent validity, correlating well with other scales. Comments suggested that the HoNOS was a useful and suitable scale for this population but psychotic symptoms and certain social factors were not sufficiently covered. CONCLUSION: The HoNOS had good validity but variable reliability. It may be better than existing scales because of the wide range of areas which it covers.

Activities of Daily Living↗

PubMed1993

The Functional Assessment of Cancer Therapy scale: development and validation of the general measure.

PURPOSE: We developed and validated a brief, yet sensitive, 33-item general cancer quality-of-life (QL) measure for evaluating patients receiving cancer treatment, called the Functional Assessment of Cancer Therapy (FACT) scale. METHODS AND RESULTS: The five-phase validation process involved 854 patients with cancer and 15 oncology specialists. The initial pool of 370 overlapping items for breast, lung, and colorectal cancer was generated by open-ended interview with patients experienced with the symptoms of cancer and oncology professionals. Using preselected criteria, items were reduced to a 38-item general version. Factor and scaling analyses of these 38 items on 545 patients with mixed cancer diagnoses resulted in the 28-item FACT-general (FACT-G, version 2). In addition to a total score, this version produces subscale scores for physical, functional, social, and emotional well-being, as well as satisfaction with the treatment relationship. Coefficients of reliability and validity were uniformly high. The scale's ability to discriminate patients on the basis of stage of disease, performance status rating (PSR), and hospitalization status supports its sensitivity. It has also demonstrated sensitivity to change over time. Finally, the validity of measuring separate areas, or dimensions, of QL was supported by the differential responsiveness of subscales when applied to groups known to differ along the dimensions of physical, functional, social, and emotional well-being. CONCLUSION: The FACT-G meets or exceeds all requirements for use in oncology clinical trials, including ease of administration, brevity, reliability, validity, and responsiveness to clinical change. Selecting it for a clinical trial adds the capability to assess the relative weight of various aspects of QL from the patient's perspective.

Adult↗