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Results for “Internal validation”

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PubMed2003

What random assignment does and does not do.

Random assignment of patients to comparison groups stochastically tends, with increasing sample size or number of experiment replications, to minimize the confounding of treatment outcome differences by the effects of differences among these groups in unknown/unmeasured patient characteristics. To what degree such confounding is actually avoided we cannot know unless we have validly measured these patient variables, but completely avoiding it is quite unlikely. Even if this confounding were completely avoided, confounding by unmeasured Patient Variable x Treatment Variable interactions remains a possibility. And the causal power of the confounding variables is no less important for internal validity than the degree of confounding.

Causality↗

PubMed2004

Validation of the postoperative nomogram for 12-year sarcoma-specific mortality.

BACKGROUND: On the basis of a prospectively followed cohort of adult patients with primary soft tissue sarcoma (STS) who were treated at Memorial Sloan-Kettering Cancer Center (MSKCC; New York, NY), a nomogram for predicting sarcoma-specific mortality was developed. Although this nomogram was found to be accurate by internal validation tests, it had not been validated in an external patient cohort, and thus its universal applicability remained unproven. METHODS: Between 1975 and 2002, 1167 adult patients (age > or = 16 years) underwent treatment for primary STS at the University of California-Los Angeles (UCLA; Los Angeles, CA). All patients treated with an ifosfamide-based chemotherapy protocol (n = 238) were excluded from the current analysis. The remaining 929 patients constituted the population on which the validation study was performed. The nomogram validation process comprised two activities. First, the extent of discrimination was quantified using the concordance index. Second, the level of calibration was assessed by grouping patients with respect to their nomogram-predicted mortality probabilities and then comparing group means with observed Kaplan-Meier estimates of disease-specific survival. RESULTS: With median follow-up intervals of 48 months for all patients and 60 months for surviving patients, the 5-year and 10-year disease-specific survival rates were 77% (95% confidence interval [CI], 74-80%) and 71% (95% CI, 67-75%), respectively. Application of the nomogram to the UCLA data set yielded a concordance index of 0.76, and the observed correspondence between predicted and actual outcomes suggested a high level of calibration. CONCLUSIONS: In the current study, the MSKCC Sarcoma Nomogram was found to provide accurate survival predictions when it was applied to an external cohort of patients who were treated at UCLA.

Adolescent↗

PubMedDate not supplied

Translation and validation of the danish version of the Bournemouth questionnaire.

OBJECTIVE: Translation, cultural adaptation, and validation of the Danish version of the Bournemouth Questionnaire (BQ). METHODS: Translation/retranslation of the English version of the BQ was done blindly and independently by 4 different individuals and adapted by an expert team. The Danish version of the BQ was tested for face validity in a sample of low-back pain (LBP) patients attending 2 chiropractic clinics. Reproducibility was tested using 28 stable LBP patients attending a hospital outpatient back-pain clinic. Finally, the Danish version of the BQ was tested for external construct validity, external longitudinal construct validity, internal consistency, and sensitivity to change against the Danish versions of the SF-36 and the Roland-Morris Disability Questionnaire (RMDQ) using 118 first-time LBP patients reporting to 1 of 7 chiropractic clinics. RESULTS: Minor changes were made after the face-validity test. Intraclass correlation coefficient of the total score for the BQ based on the 2 administrations was 0.96. Satisfactory values for the external construct validity and the external longitudinal construct validity were found using both Pearson r and Bland-Altman plots. Cronbach alpha's were .89 and .88 for the pretreatment and posttreatment scores, respectively. The Danish version of the BQ showed greater responsiveness than the SF-36 and similar responsiveness when compared with the RMDQ. CONCLUSIONS: The BQ was successfully translated and culturally adapted into Danish. The BQ was successfully tested for validity, consistency, and responsiveness against the Danish version of the SF-36 and RMDQ.

Denmark↗

PubMed1999

[Meta-analysis, megatrials, and clinical practice in cardiology].

One of the factors that raises more scepticism and concern in physicians is the combination of data from different clinical trials. In order to combine the results of different trials three requisites must be followed through: similar treatment, the patients have the same disease, and the main outcome variables must be the same. Publication bias is one important limitation of meta-analysis, and it occurs when studies with negative results are not published, which causes the effect of the treatment to be overestimated. It might seem reasonable that the demonstrated effect in the entire study population with a large sample size could be easily analyzed in different subgroups of patients, getting closer to the prediction of effect in the individual patient. This apparently obvious observation is a fallacy and subgroup analysis is often problematic. Possibly the most important condition in the analysis of subgroups is the definition of the subgroups in the design stage of the study, which can permit an adequate presight of the necessary requisites for the validity of the study. The problem of generalization of the results has been traditionally related with of extrapolation of the results to certain groups of patients not included in the clinical trial. In these cases it is important to consider other nonexperimental epidemiological studies, its internal validity and the consistency of their results. The most important characteristics that differentiate conventional clinical trials from megatrials are the following: megatrials recruit a very large and heterogenous population, with few inclusion and exclusion criteria; the only outcome variable that can be better assessed in these heterogenous conditions is eventually mortality; due to their very large sample size, results are obtained with a high level of precision (very narrow confidence intervals).

Clinical Trials as Topic↗

PubMed2006

Patients' expectations of orthodontic treatment: part 1 - development of a questionnaire.

OBJECTIVE: The development of a questionnaire to measure patients' and their parents' expectations before orthodontic treatment, and to test the reliability and validity of this measure. DESIGN: A two-stage methodology, with open-ended interviews to identify themes and concepts followed by development and testing of the questionnaire. SETTING: GKT Orthodontic Department, King's College Dental Hospital. SUBJECTS: The sample consisted of 140 participants, 70 patients aged 12-14 years, who had been referred to the orthodontic department for treatment. One parent of each patient was also recruited. MATERIALS AND METHODS: The study was in two phases. In the first phase 30 participants (15 new patients and their 15 parents) participated in open-ended interviews, which were analysed qualitatively. Information from these interviews was used to construct a questionnaire. During the second phase, the questionnaire was piloted on 10 participants, five new consecutive patients and their parents. The questionnaire was then distributed to 174 subjects (87 new patients and their 87 parents). Seventy-eight subjects (39 new patients and their 39 parents) completed the questionnaire before their orthodontic consultation. Another 96 subjects (48 new patients and their 48 parents) were invited to complete the questionnaire prior to and at their orthodontic consultation. Test-retest analysis was conducted on 22 participants (11 patients and their 11 parents), who completed the questionnaire previous to and at their orthodontic consultation, and contributed to the psychometric validation of this questionnaire. MAIN OUTCOME MEASURES: A questionnaire was devized using the key themes and concepts identified in the open-ended interviews. As a result, 10 questions, some with sub-questions were constructed using a visual analogue scale as the response format. RESULTS: The questionnaire developed had good face validity. Internal consistency of the questionnaire using Cronbach's alpha, produced an overall inter-item reliability > 0.7 along with item-total correlations > 0.3 in over 50% of questions. Test-retest reliability was statistically significant using Spearman's correlation. CONCLUSION: This study provides a valid and reliable measure of orthodontic expectations in participants aged 12-14 years and their parents.

Adolescent↗

PubMed2006

Derivation of a risk index for the prediction of massive blood transfusion in liver transplantation.

Massive blood transfusion (MBT) remains a serious and common occurrence in liver transplantation surgery. This retrospective cohort study was undertaken to identify preoperative predictors of MBT and to develop a risk index for MBT in liver transplantation. Data were retrospectively collected on all liver transplantations carried out at a single institution between January 1998 and March 2004. Multivariable logistic regression analysis was used to identify independent predictor variables of MBT, defined as >/=6 units of red blood cell concentrate (RBC) in the first 24 hours of surgery. The model was internally validated by bootstrapping. Of the 460 liver transplant recipients, 193 (42%) received >/=6 units of RBC within 24 hours of surgery. Unadjusted analyses identified 12 preoperative predictors of MBT: age, height, gender, repeat transplantation, etiology of liver failure, and preoperative laboratory values (hemoglobin concentration, platelet count, international normalized ratio for prothrombin activity [INR], albumin, total bilirubin, and creatinine). In multivariable logistic regression, 7 independent predictors of MBT were identified: age (>40 years), hemoglobin concentration (</=10.0 g/dL), INR (1.2-1.99, and >2.0), platelet count (</=70 x 10(9)/L), creatinine (>/=110 micromol/L for female subjects and >/=120 micromol/L for male subjects), albumin (< 28 g/L), and repeat transplantation. The area under the receiver-operating characteristic curve (ROC) for the model was 0.82. By using the regression beta coefficients to derive weights for each of these predictors, a risk index was developed that assigned each patient a score between 0 and 8. The ROC for this risk index was 0.79. MBT in liver transplantation surgery can be accurately predicted by 7 readily available preoperative predictors.

Adult↗

PubMed2003

Predicting mortality in patients with cirrhosis of liver with application of neural network technology.

BACKGROUND: Prediction of mortality from cirrhosis is important in planning optimal timing of liver transplantation and other interventions. We evaluated the role of the Artificial Neural Network (ANN), which uses non-linear statistics for pattern recognition in predicting one-year liver disease-related mortality using information available during initial clinical evaluation. METHODS: The ANN was constructed using software with data from a training set (n = 46) selected at random from a cohort of adult cirrhotics (n = 92). After training, validation was performed in the remaining patients (n = 46) whose outcome in terms of one-year mortality was unknown to the network. The performance of ANN was compared to those of a logistic regression model (LRM) and Child-Pugh's score (CPS). Death (related to cirrhosis/its complications) within one year of inclusion was the outcome variable. The ANN was also tested in an external validation sample (EVS, n = 62) from another hospital. RESULTS: Patients in the EVS were younger (mean age, 41 vs 45 years), infrequently of alcoholic etiology (5% vs 49%), had less severe disease (mean CPS 6.6 vs 10.8), and had lower one-year mortality (13 vs 46%). In the internal validation sample, ANN's accuracy was 91%, sensitivity 90% and specificity 92% in prediction of one-year mortality; area under the receiver-operating characteristic (ROC) curve was 0.94. The performance of the LRM (accuracy 74%) and the CPS (accuracy 55%) was significantly worse than ANN (P < 0.05, McNemar's test). Despite differences in the characteristics of the two groups, the ANN performed fairly well in the EVS (accuracy of 90%, area under curve 0.85). CONCLUSIONS: ANN can accurately predict one-year mortality in cirrhosis and is superior to CPS and LRM.

Adult↗

PubMed2005

A new tool to assess and monitor the burden of chronic cough on quality of life: Chronic Cough Impact Questionnaire.

INTRODUCTION: Chronic cough, one of the most frequent causes for a patient to consult a medical practitioner, limits the course of normal activities in everyday life of the patient affected (work, physical activities, social relations, night sleep). By now, there are few validated questionnaires for the evaluation of the impact of this symptom in the patient's quality of life (QoL). For this reason, we created a new questionnaire for the assessment of QoL in patients affected by chronic cough (Chronic Cough Impact Questionnaire, CCIQ). MATERIALS AND METHODS: In the development procedure of CCIQ an initial questionnaire of 40 items was compiled and given to a first pool of 170 patients, each coming to our attention because of chronic cough; then the 25 most significant items were detected and converted into questions evaluating the answers on a Likert scale of five steps. Consequently, this final questionnaire underwent a validation procedure to assess its construct validity, internal consistency, reliability, and responsiveness. 95 patients (44.2% F, 55.8% M) were evaluated (age 53.69 +/- 11.7 years). RESULTS: Following a statistical analysis, CCIQ showed a four-dimensional structure and good levels of internal consistency for the extracted factors: sleep/concentration (79.98), relationship (86.98), daily life impact (69.04), and mood (65.41). In stable conditions CCIQ showed a good reliability, ranged between 0.67 and 0.88. Responsiveness to clinical changes was accomplished. DISCUSSION: These results provide evidence that CCIQ has specificity enough for being a valid tool for detecting the relative burden of cough on subjective well-being, and for obtaining a global evaluation both of chronic cough impact and of treatments for it, taking into account the patient's point of view. The CCIQ was easily and quickly filled in by the patients while waiting, and it was accepted by the patients.

Adult↗

PubMed2026

Risk Prognostication After Hypomethylating Agents Combined With Venetoclax in AML: The PRISM Risk Model.

PURPOSE: As risk stratification for patients with AML treated with lower-intensity venetoclax-based therapy remains suboptimal, we developed and validated a prognostic model integrating clinical, cytogenetic, and molecular features. METHODS: We assembled a multinational data set comprising 2,092 adults with newly diagnosed AML treated with hypomethylating agents plus venetoclax (HMA + VEN). One thousand nine hundred eighteen patients with complete data were randomly divided into training (70%) and internal validation (30%) cohorts. Two independent external validation cohorts were assembled (n = 500 and n = 222). Modeling overall survival (OS), Elastic Net regression was applied in 1,000 bootstrap samples from the training cohort to select variables for a Ridge regression, which generated a continuous Prognostic Risk Integration for Survival Modeling (PRISM) score and risk categories based on tertiles (PRISM-3: low, moderate, high). These PRISM indices were then computed for the validation cohorts and compared with the 4-gene classifier (based on mutations in FLT3-ITD, N/KRAS, and TP53). RESULTS: PRISM integrated 17 clinical and genomic variables and demonstrated a linear association with OS. PRISM-3 stratified survival consistently across all cohorts (median OS: 25.1-28.8 months for low risk, 12.5-14.7 months for moderate risk, and 5.8-6.7 months for high risk; P < .001). Compared with the 4-gene classifier, PRISM-3 reassigned approximately 40% of patients (and >50% of those with favorable risk) and demonstrated significantly better discrimination in validation cohorts (C-index 0.63-0.65 v 0.59-0.61; P < .05). CONCLUSION: PRISM is a validated prognostic model for patients with AML receiving HMA + VEN that improves survival risk stratification beyond current standard tools and supports individualized, risk-adapted clinical decision making. The model, the PRISM-AML Risk Calculator, is publicly available.

Humans↗

PubMed2005

Molecular staging of lymph nodes from patients with esophageal adenocarcinoma.

PURPOSE: This study was designed to evaluate molecular markers for the detection of micrometastasis in esophageal adenocarcinoma, define algorithms to distinguish positive from benign lymph nodes and to validate these findings in an independent tissue set and in patients with p(N0) esophageal adenocarcinoma. EXPERIMENTAL DESIGN: Potential markers were identified through literature and database searches. All markers were analyzed by quantitative reverse transcription (QRT)-PCR on a limited set of primary tumors and benign lymph nodes. Selected markers were further evaluated on a larger tissue set and classification algorithms were generated for individual markers and combinations. Algorithms were statistically validated internally as well as externally on an independent set of lymph nodes. Selected markers were then used to identify occult disease in lymph nodes from 34 patients with p(N0) esophageal adenocarcinoma. RESULTS: Thirty-nine markers were evaluated, six underwent further analysis and five were analyzed in the external validation study. Two markers provided perfect classification in both the screening and validation sets, although parametric bootstrap analysis estimated 2% to 3% optimism in the observed classification accuracy. Several marker combinations also gave perfect classification in the observed data sets, and estimates of optimism were lower, implying more robust classification than with individual markers alone. Five of thirty-four patients with esophageal adenocarcinoma had positive nodes by multimarker QRT-PCR analysis and disease-free survival was significantly worse in these patients (P = 0.0023). CONCLUSIONS: We have identified novel QRT-PCR markers for the detection of occult lymph node disease in patients with esophageal adenocarcinoma. The objective nature of QRT-PCR results, and the ability to detect occult metastases, make this an attractive alternative to routine pathology.

Adenocarcinoma↗

PubMed1990

A methodological framework for the design of research on the evaluation of residents.

This paper describes a construct validation framework for research on the selection and evaluation of residents. The application of the proposed methodology to surgery residents is described. The need to measure non-cognitive and neuropsychological factors in addition to cognitive knowledge and technical ability is emphasized, and a research strategy that integrates theory formulation, internal validation, and external validation is presented. In this context, residents' competence is viewed as a multivariate construct that requires validation through longitudinal empirical studies and the use of multivariate statistical approaches.

Clinical Competence↗

PubMed2005

Derivation and validation of a prognostic model for pulmonary embolism.

RATIONALE: An objective and simple prognostic model for patients with pulmonary embolism could be helpful in guiding initial intensity of treatment. OBJECTIVES: To develop a clinical prediction rule that accurately classifies patients with pulmonary embolism into categories of increasing risk of mortality and other adverse medical outcomes. METHODS: We randomly allocated 15,531 inpatient discharges with pulmonary embolism from 186 Pennsylvania hospitals to derivation (67%) and internal validation (33%) samples. We derived our prediction rule using logistic regression with 30-day mortality as the primary outcome, and patient demographic and clinical data routinely available at presentation as potential predictor variables. We externally validated the rule in 221 inpatients with pulmonary embolism from Switzerland and France. MEASUREMENTS: We compared mortality and nonfatal adverse medical outcomes across the derivation and two validation samples. MAIN RESULTS: The prediction rule is based on 11 simple patient characteristics that were independently associated with mortality and stratifies patients with pulmonary embolism into five severity classes, with 30-day mortality rates of 0-1.6% in class I, 1.7-3.5% in class II, 3.2-7.1% in class III, 4.0-11.4% in class IV, and 10.0-24.5% in class V across the derivation and validation samples. Inpatient death and nonfatal complications were <or= 1.1% among patients in class I and <or= 1.9% among patients in class II. CONCLUSIONS: Our rule accurately classifies patients with pulmonary embolism into classes of increasing risk of mortality and other adverse medical outcomes. Further validation of the rule is important before its implementation as a decision aid to guide the initial management of patients with pulmonary embolism.

Acute Disease↗

PubMedDate not supplied

[Quality of life assessment in Inflammatory Bowel Disease (IBD): German version of the Inflammatory Bowel Disease Questionnaire (IBDQ-D; disease-specific instrument for quality of life assessment) -- first application and comparison with international investigations].

BACKGROUND: Health-related quality of life (HRQOL) is an important outcome-parameter in health research and care. The aim of the working group Quality of Life in the Competence Network Inflammatory Bowel Disease (IBD; in the original German: "Kompetenznetz chronisch entzündliche Darmerkrankungen") is to generate instruments for assessment of HRQOL and its implementation as standards in clinical trials, health care and research in IBD. METHODS: The Inflammatory Bowel Disease Questionnaire (IBDQ) is an international validated disease specific instrument for HRQOL-assessment. A German version of the IBDQ was elaborated and tested in 415 outpatients with Crohn's disease (CD, n = 306) and ulcerative colitis (UC, n = 109). The aim of the study was to compare the results of HRQOL-assessment (IBDQ-D) with international investigations, to correlate HRQOL results with disease activity and to preform a pretest of psychometric properties. RESULTS: International data suggest that the IBDQ-D is a suitable instrument for HRQOL-assessment in CD and UC. For both disease a statistically significant negative correlation with disease activity was found. Tested psychometric properties do not suggest that a revision of the IBDQ-D is required. The IBDQ-D offers the HRQOL-assessment as an primary or secondary outcome in clinical trials in IBD in Germany.

Adult↗

PubMed2006

Use and effectiveness of warfarin in Medicare beneficiaries with atrial fibrillation.

BACKGROUND AND PURPOSE: More than 2 million Americans have atrial fibrillation, and without antithrombotic therapy, their stroke rate is increased 5-fold. In randomized controlled trials, warfarin prevented 65% of ischemic strokes (hazard ratio [HR], 0.35; 95% CI, 0.26 to 0.48) compared with no antithrombotic therapy. However, the effectiveness of warfarin therapy outside of clinical trials is unknown, especially in black and Hispanic populations. Our goal was to quantify use of warfarin therapy, frequency of International Normalized Ratio monitoring, and effectiveness for stroke prophylaxis in Medicare beneficiaries with atrial fibrillation. METHODS: This was a cohort study of Medicare beneficiaries with atrial fibrillation who were hospitalized between March 1998 and April 1999 in all 50 US states. The primary outcome was incident hospitalizations for ischemic stroke based on validated International Classification of Diseases, 9th Revision, Clinical Modification codes. RESULTS: Two thirds of ideal anticoagulation candidates were prescribed warfarin on hospital discharge. In unadjusted analyses, the stroke rates per 100 patient years of warfarin therapy were 5.2 in (non-Hispanic) white Medicare beneficiaries, 10.6 in black beneficiaries, and 12.2 in Hispanic beneficiaries. After adjusting for comorbid conditions, warfarin prescription was more frequent and monitoring more regular in white Medicare beneficiaries than in black or Hispanic beneficiaries (P<0.0001). Warfarin use was associated with 35% fewer ischemic strokes (HR, 0.65; 95% CI, 0.55 to 0.76) compared with no antithrombotic therapy but was less effective in black and Hispanic beneficiaries (P for interaction=0.048). CONCLUSIONS: The use, monitoring, and effectiveness of warfarin therapy are suboptimal in Medicare beneficiaries, especially in black and Hispanic beneficiaries.

Aged↗

PubMed2000

[Illness-related stress in psoriasis vulgaris. Validation of the "Psoriasis Daily Stress Inventory"].

BACKGROUND AND OBJECTIVE: Illness specific stress plays an important part in the daily life of psoriatic patients. Until now for the measurement of relevant aspects of daily stress only the "Psoriasis Life Stress Inventory" (PLSI) of Gupta & Gupta exists; with the "Psoriasis-Alltagsstress-Inventar" (PAI), a German version of the PLSI is presented and its psychometric properties are discussed. PATIENTS/METHODS: 385 in-patients completed the PAI. The internal validity was examined by factor analysis. Moreover, the correlations between the PAI total score and sociodemographic parameters (ANOVA) and extent of skin involvement (multiple regression) were determined. RESULTS: The PLSI score proves to be sufficiently independent of age, sex, age at onset, and general extent of skin involvement. However, affections of the hands, the lower abdomen and the genitals show a strong influence on the total score. We found marked interrelations with the stigmatization feeling ("Questionnaire on Experience with Skin Complaints" QES, Schmid-Ott et al. 1998). CONCLUSIONS: The results suggest that the PAI is a useful and psychologically relevant questionnaire for psoriatic patients.

Adult↗

PubMed2001

Principles of effectiveness trials and their implementation in VA Cooperative Study #430: 'Reducing the efficacy-effectiveness gap in bipolar disorder'.

Despite the availability of efficacious treatments for bipolar disorder, their effectiveness in general clinical practice is greatly attenuated, resulting in what has been called an 'efficacy-effectiveness gap'. In designing VA Cooperative Studies Program (CSP) Study #430 to address this gap, nine principles for conducting an effectiveness (in contrast to an efficacy) study were identified. These principles are presented and discussed, with specific aspects of CSP #430 serving as illustrations of how they can be implemented in an actual study. CSP #430 hypothesizes that an integrated, clinic-based treatment delivery system that emphasizes (1) algorithm-driven somatotherapy, (2) standardized patient education, and (3) easy access to a single primary mental health care provider to maximize continuity-of-care, will address the efficacy-effectiveness gap and improve disease, functional, and economic outcome. It is an 11-site, randomized controlled clinical trial of this multi-modal, clinic-based intervention versus usual VA care running from 1997 to 2003. The trial has enrolled 191 subjects in each arm, using minimal exclusion criteria to maximize the external validity of the study. Subjects are followed for 3 years. The intervention is highly specified in a series of operations manuals for each of the three components. Several continuous quality improvement (CQI) interventions, process measures, and statistical techniques deal with drift of care in both the intervention and usual care arms to ensure the internal validity of the study. CSP #430 is designed to have impact well beyond the VA, since it evaluates a basic health care operational principle: that augmenting ambulatory access for major mental illness will improve outcome and reduce overall treatment costs. If results are positive, this study will provide a reason to reconsider the prevailing trend toward limitation of ambulatory services that is characteristic of many managed care systems today.

Activities of Daily Living↗

PubMed1979

Threats to the validity of emergency medical services evaluation: a case study of mobile intensive care units.

Much of the literature concerning emergency medical services evaluation has been criticized as unconvincing. Several sources of invalidity have comprised the interpretability of these studies. When true randomized experiments cannot be accomplished, quasi-experimental research designs offer greater interpretability than the more often used pre-experimental designs. In using quasi-experimental research designs, special attention must be given to threats to internal validity. A case study describes an evaluation of mobile intensive care units. The paper describes eighteen threats to the validity of the evaluation, as well as the methods used for their control. Whether or not evaluators can control all of the threats to the validity of their studies, these threats should be identified and their potential effects assessed wherever possible.

Analysis of Variance↗

PubMed2000

The SWAL-QOL outcomes tool for oropharyngeal dysphagia in adults: II. Item reduction and preliminary scaling.

The SWAL-QOL outcomes tool was constructed for use in clinical research for patients with oropharyngeal dysphagia. The SWAL-QOL was constructed a priori to enable preliminary psychometric analyses of items and scales before its final validation. This article describes data analysis from a pretest of the SWAL-QOL. We evaluated the different domains of the SWAL-QOL for respondent burden, data quality, item variability, item convergent validity, internal consistency reliability as measured by Cronbach's alpha, and range and skewness of scale scores upon aggregation and floor and ceiling effects. The item reduction techniques outlined reduced the SWAL-QOL from 185 to 93 items. The pretest of the SWAL-QOL afforded us the opportunity to select items for the ongoing validation study which optimally met our a priori psychometric criteria of high data quality, normal item distributions, and robust evidence of item convergent validity.

Aged↗