TY - JOUR
T1 - Development of a new Rasch-based scoring algorithm for the National Eye Institute Visual Functioning Questionnaire to improve its interpretability
AU - Petrillo, Jennifer
AU - Bressler, Neil M.
AU - Lamoureux, Ecosse
AU - Ferreira, Alberto
AU - Cano, Stefan
N1 - Funding Information:
The authors take full responsibility for the content of the manuscript but would like to thank Dr. Ben Dean and Dr. Paul Overton from Oxford PharmaGenesis Ltd. for editorial support in developing the manuscript. Editorial support was funded by Novartis Pharma AG, Basel, Switzerland. The authors would also like to thank Professor Paul Lee from the University of Michigan, MI, USA, for his contributions to this study and manuscript.
Publisher Copyright:
© 2017 The Author(s).
PY - 2017/8/14
Y1 - 2017/8/14
N2 - Background: The NEI VFQ-25 has undergone psychometric evaluation in patients with varying ocular conditions and the general population. However, important limitations which may affect the interpretation of clinical trial results have been previously identified, such as concerns with reliability and validity. The purpose of this study was to evaluate the National Eye Institute Visual Functioning Questionnaire (NEI VFQ25) and make recommendations for a revised scoring structure, with a view to improving its psychometric performance and interpretability. Methods: Rasch Measurement Theory analyses were conducted in two stages using pooled baseline NEI VFQ25 data for 2487 participants with retinal diseases enrolled in six clinical trials. In stage 1, we examined: scale-to-sample targeting; thresholds for item response options; item fit statistics; stability; local dependence; and reliability. In stage 2, a post-hoc revision of the scoring structure (VFQ-28R) was created and psychometrically re-evaluated. Results: In stage 1, we found that the NEI VFQ25 was mis-targeted to the sample, and had disordered response thresholds (15/25 items) and mis-fitting items (8/25 items). However, items appeared to be stable (differential item functioning for three items), have minimal item dependency (one pair of items) and good reliability (person-separation index, 0.93). In stage 2, the modified Rasch-scored NEI VFQ28R was assessed. It comprised two broad domains: Activity Limitation (19 items) and Socio-Emotional Functioning (nine items). The NEI VFQ28R demonstrated improved performance with fewer disordered response thresholds (no items), less item misfit (three items) and improved population targeting (reduced ceiling effect) compared with the NEI VFQ25. Conclusions: Compared with the original version, the proposed NEI VFQ28R, with Rasch-based scoring and a two-domain structure, appears to offer improved psychometric performance and interpretability of the vision-related quality of life scale for the population analysed.
AB - Background: The NEI VFQ-25 has undergone psychometric evaluation in patients with varying ocular conditions and the general population. However, important limitations which may affect the interpretation of clinical trial results have been previously identified, such as concerns with reliability and validity. The purpose of this study was to evaluate the National Eye Institute Visual Functioning Questionnaire (NEI VFQ25) and make recommendations for a revised scoring structure, with a view to improving its psychometric performance and interpretability. Methods: Rasch Measurement Theory analyses were conducted in two stages using pooled baseline NEI VFQ25 data for 2487 participants with retinal diseases enrolled in six clinical trials. In stage 1, we examined: scale-to-sample targeting; thresholds for item response options; item fit statistics; stability; local dependence; and reliability. In stage 2, a post-hoc revision of the scoring structure (VFQ-28R) was created and psychometrically re-evaluated. Results: In stage 1, we found that the NEI VFQ25 was mis-targeted to the sample, and had disordered response thresholds (15/25 items) and mis-fitting items (8/25 items). However, items appeared to be stable (differential item functioning for three items), have minimal item dependency (one pair of items) and good reliability (person-separation index, 0.93). In stage 2, the modified Rasch-scored NEI VFQ28R was assessed. It comprised two broad domains: Activity Limitation (19 items) and Socio-Emotional Functioning (nine items). The NEI VFQ28R demonstrated improved performance with fewer disordered response thresholds (no items), less item misfit (three items) and improved population targeting (reduced ceiling effect) compared with the NEI VFQ25. Conclusions: Compared with the original version, the proposed NEI VFQ28R, with Rasch-based scoring and a two-domain structure, appears to offer improved psychometric performance and interpretability of the vision-related quality of life scale for the population analysed.
KW - National Eye Institute Visual Functioning Questionnaire
KW - Rasch Measurement Theory
KW - Vision-related quality of life
UR - http://www.scopus.com/inward/record.url?scp=85027271460&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=85027271460&partnerID=8YFLogxK
U2 - 10.1186/s12955-017-0726-5
DO - 10.1186/s12955-017-0726-5
M3 - Article
C2 - 28807029
AN - SCOPUS:85027271460
SN - 1477-7525
VL - 15
JO - Health and Quality of Life Outcomes
JF - Health and Quality of Life Outcomes
IS - 1
M1 - 157
ER -