title: Impact of Rating Scale Categories on Reliability and Fit Statistics of the Malay Spiritual Well-Being Scale using Rasch Analysis.
abstract: BACKGROUND
  Few studies have employed the item response theory in examining reliability. We conducted this study to examine the effect of Rating Scale Categories (RSCs) on the reliability and fit statistics of the Malay Spiritual Well-Being Scale, employing the Rasch model.
  
  
  METHODS
  The Malay Spiritual Well-Being Scale (SWBS) with the original six; three and four newly structured RSCs was distributed randomly among three different samples of 50 participants each.
  
  
  RESULTS
  The mean age of respondents in the three samples ranged between 36 and 39 years old. The majority was female in all samples, and Islam was the most prevalent religion among the respondents. The predominating race was Malay, followed by Chinese and Indian. The original six RSCs indicated better targeting of 0.99 and smallest model error of 0.24. The Infit Mnsq (mean square) and Zstd (Z standard) of the six RSCs were "1.1"and "-0.1"respectively. The six RSCs achieved the highest person and item reliabilities of 0.86 and 0.85 respectively. These reliabilities yielded the highest person (2.46) and item (2.38) separation indices compared to other the RSCs.
  
  
  CONCLUSIONS
  The person and item reliability and, to a lesser extent, the fit statistics, were better with the six RSCs compared to the four and three RSCs.
authors.affiliation: Department of Community Medicine, Faculty of Medicine and Defence Health. National Defence University of Malaysia, Sungai Besi Camp, 57000 Kuala Lumpur, Malaysia.
authors.forename: Aqil Mohammad
authors.initials: AM
authors.lastname: Daher
authors.affiliation: Department of Psychiatry, faculty of Medicine. University Teknologi MARA, Taman Prima Selayang, 68100 Batu Caves Selangor, Malaysia.
authors.forename: Syed Hassan
authors.initials: SH
authors.lastname: Ahmad
authors.affiliation: Department of Community Medicine, Faculty of Medicine, MAHSA University, 50490 Kuala Lumpur, Malaysia.
authors.forename: Than
authors.initials: T
authors.lastname: Winn
authors.affiliation: Population Health and Preventive Medicine, Faculty of Medicine, University Teknologi MARA, Jalan Hospital, 47000 Sungai Buloh, Selangor, Malaysia.
authors.forename: Mohd Ikhsan
authors.initials: MI
authors.lastname: Selamat
keywords: analysis; rating scale; reliability; spirituality