Evaluating the Quality of Life (QoL) in Blind War Veterans, Using Rasch Model

Introduction & Quality of life can be an important index for determining the social status and performance evaluation of presented services. As the quality of life cannot be measured directly، it can be spot as a latent variable. In this article، Rasch model is used as a latent trait model for evaluating the quality of life. This was a cross-sectional study. The population under study included all 71 blind war veterans، that their data was collected in 2011 from SF36 questionnaire with assistance of the Foundation of Martyrs and Veterans Affairs. The quality of life and the difficulty of items were estimated، using Rasch model and Winsteps. The mean (± SD) age and blindness duration range of veterans were 48. 97 (± 10. 655) and 25. 74 (± 3. 692)، respectively. They also averagely suffered from 2 other ulcers which accompanied their blindness. Comparison of estimated QoL، using RM، and those from SF36 showed that as far as physical، mental and total correlation is concerned، there is a direct and positive correlation between these two. But the standard error of Rasch estimation in physical and total dimensions was lower than those from SF36. Rasch model gives more precise estimations than SF36 measurements، and it also gives an estimation of the difficulty parameters with statistical modeling.