Applying generalizability theory methods to assess continuity and change on the Adolescent Quality of Life-Mental Health Scale (AQOL-MHS)

Development and Validation of the Chronic Gastritis Scale Under the System of Quality of Life Instruments for Chronic Diseases QLICD-CG Based on Classical Test Theory and Generalizability Theory

BACKGROUND AND AIM

Quality of life (QOL) for patients with chronic gastritis (CG) is of interest worldwide and disease-specific instruments are needed for clinical research and practice. This paper focused on the development and validation of the CG scale under the system of Quality of Life Instruments for Chronic Diseases (QLICD-CG) by the modular approach and both classical test theory and generalizability theory.

METHODS

The QLICD-CG was developed based on programmed decision procedures including multiple nominal and focus group discussions, in-depth interviews and quantitative statistical procedures. Based on the data measuring QOL 3 times before and after treatments from 142 inpatients with CG, the psychometric properties of the scale were evaluated with respect to validity, reliability and responsiveness employing correlation analysis, multi-trait scaling analysis, factor analyses, t tests and also G studies and D studies of generalizability theory analysis.

RESULTS

Correlation, multi-trait scaling and factor analyses confirmed good construct validity and criterion-related validity when using SF-36 as a criterion. The internal consistency α for all domains were higher than 0.70 except for the social domain (0.62). Test-retest reliability coefficients (Pearson r and intraclass correlations) for the overall score and all domains were higher than 0.80 except for the social domain (0.77), while they were ranging between 0.72 to 0.94 at facets level; The overall score and scores for all domains/facets had statistically significant changes (P<0.01) after treatments except for facets of social effects and sexual function with standardized response mean ranging from 0.04 to 1.03, but from 0.34 to 1.03 for the domain level scores. G-coefficients and index of dependability (Ф coefficients) confirmed the reliability of the scale further with more exact variance components, and decision information on number of items changing.

CONCLUSIONS

The QLICD-CG could be used as a useful instrument in assessing QoL for patients with CG, with good psychometric properties including validity, reliability and responsiveness and also several advantages.

Psychometric properties of instruments assessing exercise in patients with eating disorders: a systematic review

BACKGROUND

Research has identified factors specific to exercise in eating disorder patients such as affect regulation and compulsivity. Existing measures of exercise behaviour which were not originally designed for eating disorder patients may not adequately assess these factors. The aim of this systematic review is to identify and assess the psychometric properties of all self-report measures of exercise designed to be used with eating disorder patients.

METHOD

A systematic review was conducted following the PRISMA guidelines. MedLine, Scopus and PsycINFO were systematically searched. A total of 12 studies examining two measures, the Exercise and Eating Disorders and the Compulsive Exercise Test, met inclusion criteria.

RESULTS

Validation studies showed promising results for both tests and established internal consistency, concurrent and convergent validity, and construct validity. The factor structure of the Compulsive Exercise Test was not confirmed in the majority of the studies included in this review, while there are only two studies conducting factor analysis on the Exercise and Eating Disorders.

CONCLUSION

The two measures identified by this systematic review represent the current research on measures of compulsive exercise for eating disorder patients. Further research is needed to confirm a factor structure and validate both the Compulsive Exercise Test and the Exercise and Eating Disorders in more diverse clinical samples.

Distinguishing transient versus stable aspects of depression in New Zealand Pacific Island children using Generalizability Theory

BACKGROUND

The distinction between temporary versus enduring or state/trait aspects of depression is important. More precise distinction would improve understanding of the aetiology of depression and those aspects most amenable to intervention thus identifying more homogeneous, dynamic targets for clinical trials. Generalizability Theory has been proposed as useful for disentangling state and trait components of psychopathology.

METHODS

We applied Generalizability Theory to determine the relative contributions of temporary and enduring aspects of depression in a widely used screening measure of depression the - 10-item Children's Depression Inventory (CDI-10; Kovacs, 1985). Participants were children of Pacific Island descent living in New Zealand (n = 668). Data were collected at ages - 9, 11, and 14 years.

RESULTS

The CDI-10 demonstrated acceptable generalizability across occasions (G = 0.79) with about one third of variance in total scores attributed to temporary and two thirds to more enduring aspects of depression. There were no other significant sources of error variance. Two items were identified as more sensitive than the remaining eight to more dynamic symptoms.

LIMITATIONS

Studies with briefer test-retest intervals are warranted. Use of this Pacific Island cohort limits generalizability of findings to other cultures and ethnicities. No data were collected on whether participants had received intervention for depression.

CONCLUSIONS

While the CDI-10 reliably measures both stable and transient aspects of depression in children, the scale does not permit clear distinction between them. We advocate application of Generalizability Theory for developing state/trait depression measures and determining which existing measures are most suitable for capturing modifiable features of depression.

Reliability analysis of the Chinese version of the Functional Assessment of Cancer Therapy - Leukemia (FACT-Leu) scale based on multivariate generalizability theory

Background

The Functional Assessment of Cancer Therapy–Leukemia (FACT-Leu) scale, a leukemia-specific instrument for determining the health-related quality of life (HRQOL) in patients with leukemia, had been developed and validated, but there have been no reports on the development of a simplified Chinese version of this scale. This is a new exploration to analyze the reliability of the HRQOL measurement using multivariate generalizability theory (MGT). This study aimed to develop a Chinese version of the FACT-Leu scale and evaluate its reliability using MGT to provide evidence to support the revision and improvement of this scale.

Methods

The Chinese version of the FACT-Leu scale was developed by four steps: forward translation, backward translation, cultural adaptation and pilot-testing. The HRQOL was measured for eligible inpatients with leukemia using this scale to provide data. A single-facet multivariate Generalizability Study (G-study) design was demonstrated to estimate the variance–covariance components and then several Decision Studies (D-studies) with varying numbers of items were analyzed to obtain reliability coefficients and to understand how much the measurement reliability could be vary as the number of items in MGT changes.

Results

One-hundred and one eligible inpatients diagnosed with leukemia were recruited and completed the HRQOL measurement at the time of admission to the hospital. In the G-study, the variation component of the patient-item interaction was largest while the variation component of the item was the smallest for the four of five domains, except for the leukemia-specific (LEUS) domain. In the D-study, at the level of domain, the generalizability coefficients (G) and the indexes of dependability (Ф) for four of the five domains were approximately equal to or greater than 0.80 except for the Emotional Well-being (EWB) domain (>0.70 but <0.80). For the overall scale, the composite G and composite Ф coefficients were greater than 0.90. Based on the G coefficient and Ф coefficient, two decision options for revising this scale considering the number of items were obtained: one is a 37-item version while the other is a 45-item version.

Conclusion

The Chinese version of the FACT-Leu scale has good reliability as a whole based on the results of MGT and the implementation of MGT could lead to more informed decisions in complex questionnaire design and improvement.

Electronic supplementary material

The online version of this article (doi:10.1186/s12955-017-0664-2) contains supplementary material, which is available to authorized users.