Date of Award


Document Type

Masters Thesis

Degree Name


Organizational Unit

Morgridge College of Education, Research Methods and Information Science, Research Methods and Statistics

First Advisor

Antonio Olmos, Ph.D.

Second Advisor

Kathy Green

Third Advisor

Jennifer Cornish


Reliability generalization, Brief symptom inventory


Reliability generalization (RG) is a meta-analytic method that aims to assess the variability of test score reliability across studies and identify the sources of this variability. In this study, a reliability generalization analysis was performed on studies of the Brief Symptom Inventory-18 (BSI-18) to examine the variability in Cronbach's alpha reliability estimates reported in the literature. This inventory was chosen because of its extensive use in counseling and medical settings and documented reliability and validity. The database that was consulted to collect articles was PsycInfo. The reported Cronbach's alphas were obtained to assess whether defined moderator variables affected reliability estimates. Out of the 161 references located, 48 studies met the selection criteria. For the Global Severity Index (GSI), the mean reliability was 0.91, 0.77 for the Somatic subscale, 0.85 for the Depression subscale, and 0.83 for the Anxiety subscale. The moderator analyses led to a predictive model where the type of population (clinical vs. nonclinical) for the GSI, and gender for the Somatic subscale were significant. Finally, clinical implications of the results are discussed.

Publication Statement

Copyright is held by the author. User is responsible for all copyright compliance.

Rights Holder

Dareen Taha Alzahrani


Received from ProQuest

File Format




File Size

57 p.