TY - JOUR
T1 - Comparison of Rasch and summated rating scales constructed from SF-36 physical functioning items in seven countries
T2 - Results from the IQOLA Project
AU - Raczek, Anastasia E.
AU - Ware, John E.
AU - Bjorner, Jakob B.
AU - Gandek, Barbara
AU - Haley, Stephen M.
AU - Aaronson, Neil K.
AU - Apolone, Giovanni
AU - Bech, Per
AU - Brazier, John E.
AU - Bullinger, Monika
AU - Sullivan, Marianne
PY - 1998/11
Y1 - 1998/11
N2 - Rasch models for polytomous items were used to assess the scaling assumptions and compare item response patterns in the 10-item SF-36 physical functioning scale (PF-10) for general population respondents in Denmark, Germany, Italy, the Netherlands, Sweden, the United Kingdom, and the United States. The Rasch model of physical functioning developed in the United States was compared to models for other countries, and each country was compared to a multinational composite. Strong scale congruence across the seven countries was demonstrated; items that varied between countries and from the composite may reflect unique cultural response patterns or differences in translation. Scoring algorithms based on the Rasch model for each country were superior to the current Likert scoring in tests of relative validity (RV) in discriminating among age groups in all countries. In relation to the Likert PF-10 scoring (RV = 1.00), scores estimated using the Rasch rating scale model achieve a median RV of 1.31 (range: 1.01-1.59), while the Rasch partial credit model attained a median RV of 1.44 (range: 1.01-2.23). Rasch models hold good potential for improving health status measures, estimating individual scores when responses to scale items are missing, and equating scores across countries.
AB - Rasch models for polytomous items were used to assess the scaling assumptions and compare item response patterns in the 10-item SF-36 physical functioning scale (PF-10) for general population respondents in Denmark, Germany, Italy, the Netherlands, Sweden, the United Kingdom, and the United States. The Rasch model of physical functioning developed in the United States was compared to models for other countries, and each country was compared to a multinational composite. Strong scale congruence across the seven countries was demonstrated; items that varied between countries and from the composite may reflect unique cultural response patterns or differences in translation. Scoring algorithms based on the Rasch model for each country were superior to the current Likert scoring in tests of relative validity (RV) in discriminating among age groups in all countries. In relation to the Likert PF-10 scoring (RV = 1.00), scores estimated using the Rasch rating scale model achieve a median RV of 1.31 (range: 1.01-1.59), while the Rasch partial credit model attained a median RV of 1.44 (range: 1.01-2.23). Rasch models hold good potential for improving health status measures, estimating individual scores when responses to scale items are missing, and equating scores across countries.
KW - International comparisons
KW - Item response theory
KW - Physical functioning
KW - Rasch model
KW - SF-36 Health Survey
KW - Translations
KW - Validity
UR - http://www.scopus.com/inward/record.url?scp=0032211655&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0032211655&partnerID=8YFLogxK
U2 - 10.1016/S0895-4356(98)00112-7
DO - 10.1016/S0895-4356(98)00112-7
M3 - Article
C2 - 9817138
AN - SCOPUS:0032211655
VL - 51
SP - 1203
EP - 1214
JO - American journal of syphilis, gonorrhea, and venereal diseases
JF - American journal of syphilis, gonorrhea, and venereal diseases
SN - 0895-4356
IS - 11
ER -