Revised 15-item Glasgow Benefit Inventory with five factors based on analysis of a large population study of medical and surgical otorhinolaryngological interventions

Abstract

OBJECTIVES: To review, using confirmatory factor analysis, the widely used 18-question Glasgow Benefit Inventory [GBI] that has three factors. Thereafter to develop, using exploratory factor analysis, a more coherent, revised version of the GBI. DESIGN: Confirmatory and exploratory factor analysis of a large national GBI data set of ORL interventions. SETTING: Adult otorhinolaryngology outpatient clinics in six University Hospital departments. PARTICIPANTS: One thousand nine hundred eighty adult patients who had complete GBI data and who underwent an active (medical or surgical) intervention, out of the total data set of 9005 patients from the original Scottish ENT Outcome Study [SENTOS]. RESULTS: One of the 18 questions was discarded from the data base because it was not answered by 8% of respondents. Two of the original factors remained (Physical Health, renamed General Health, and Social Support, renamed Support). The General factor was split into three new factors (Quality of Life, Self-Confidence and Social Involvement). The three new factors were found to give additional information regarding the area of benefit. This reduced number of questions does not make any material difference to the results of the >196 existing GBI papers in the literature. CONCLUSION: A 15-question GBI with five factors is provided that is more explanatory of the areas of benefit.