OBJECTIVE: To deal with the question of whether a 5-point response Likert scale should be changed to a 3-point scale when used in the field testing of people with intellectual disabilities (IDs), which was raised after the pilot study of World Health Organization Quality of Life (WHOQOL)-DIS, a module being developed with the World Health Organization measure of quality of life for disabilities. METHODS: Three possible ways were used to generate hypothetical data by merging a 5-point scale into a 3-point scale. The analyses were based on both item response theory and classical measurement theory. The partial credit model for polytomous response was performed for item evaluation; the confirmatory factor analysis was used to check construct validity, the Cronbach's alpha for domain reliability, and correlation analyses for the relationship between the 5-point scale and the generated 3-point scale. RESULTS: Most items with a 5-point response scale had disordered response options and/or unequal-length intervals between successive response options; these deficiencies were removed or improved without decline of validity and reliability in the hypothetical data of 3-point scales. CONCLUSION: Instead of the 5-point scale, a 3-point scale could be used for IDs in the field test of developing the module WHOQOL-DIS.
OBJECTIVE: To deal with the question of whether a 5-point response Likert scale should be changed to a 3-point scale when used in the field testing of people with intellectual disabilities (IDs), which was raised after the pilot study of World Health Organization Quality of Life (WHOQOL)-DIS, a module being developed with the World Health Organization measure of quality of life for disabilities. METHODS: Three possible ways were used to generate hypothetical data by merging a 5-point scale into a 3-point scale. The analyses were based on both item response theory and classical measurement theory. The partial credit model for polytomous response was performed for item evaluation; the confirmatory factor analysis was used to check construct validity, the Cronbach's alpha for domain reliability, and correlation analyses for the relationship between the 5-point scale and the generated 3-point scale. RESULTS: Most items with a 5-point response scale had disordered response options and/or unequal-length intervals between successive response options; these deficiencies were removed or improved without decline of validity and reliability in the hypothetical data of 3-point scales. CONCLUSION: Instead of the 5-point scale, a 3-point scale could be used for IDs in the field test of developing the module WHOQOL-DIS.
Authors: Anu Birla Bakshi; Shiou-Liang Wee; Charlene Tay; Loong-Mun Wong; Ian Yi-Onn Leong; Reshma A Merchant; Nan Luo Journal: BMC Health Serv Res Date: 2012-08-16 Impact factor: 2.655
Authors: Anupa Pathak; Saurab Sharma; Allen W Heinemann; Paul W Stratford; Daniel Cury Ribeiro; J Haxby Abbott Journal: Qual Life Res Date: 2020-09-23 Impact factor: 3.440