Evaluation of the Patient-Reported Outcomes Information System (PROMIS®) Spanish-language physical functioning items
- First Online:
- 349 Downloads
To evaluate the equivalence of the PROMIS® physical functioning item bank by language of administration (English versus Spanish).
The PROMIS® wave 1 English-language physical functioning bank consists of 124 items, and 114 of these were translated into Spanish.
Item frequencies, means and standard deviations, item-scale correlations, and internal consistency reliability were calculated. The IRT assumption of unidimensionality was evaluated by fitting a single-factor confirmatory factor analytic model. IRT threshold and discrimination parameters were estimated using Samejima’s Graded Response Model. DIF by language of administration was evaluated.
Item means ranged from 2.53 (SD = 1.36) to 4.62 (SD = 0.82). Coefficient alpha was 0.99, and item-rest correlations ranged from 0.41 to 0.89. A one-factor model fits the data well (CFI = 0.971, TLI = 0.970, and RMSEA = 0.052). The slope parameters ranged from 0.45 (“Are you able to run 10 miles?”) to 4.50 (“Are you able to put on a shirt or blouse?”). The threshold parameters ranged from −1.92 (“How much do physical health problems now limit your usual physical activities (such as walking or climbing stairs)?”) to 6.06 (“Are you able to run 10 miles?”). Fifty of the 114 items were flagged for DIF based on an R2 of 0.02 or above criterion. The expected total score was higher for Spanish- than English-language respondents.
English- and Spanish-speaking subjects with the same level of underlying physical function responded differently to 50 of 114 items. This study has important implications in the study of physical functioning among diverse populations.
KeywordsPROMIS® item banks IRT Physical function Spanish items
- 2.Shorris, E. (1992). Latinos: A biography of the people. New York: W.W. Norton & Co.Google Scholar
- 3.Morales, L., Kington, R., Valdez, R., et al. (2002). Socioeconomic, cultural, and behavioral factors affecting hispanic health outcomes. Journal of Health Care Poor Underserved, 13(4), 477–503.Google Scholar
- 4.California State Department of Finance. (2002). Current population survey report: March 2001 data. Sacramento, November 2002.Google Scholar
- 5.Los Angeles County Department of Health Services. (2000). Data collection and analysis division. Los Angeles: Vital Statistics of Los Angeles County.Google Scholar
- 6.U.S. Census Bureau: Census 2000 US Demographic profile and population center. Washington, DC 20033 (NP-T4-F) Projections of the total resident population by 5-year age groups, race, and Hispanic origin with special age categories.Google Scholar
- 7.U.S. Census Bureau: Current population reports (P25-1130) Population projections of the US by age, sex, race, and Hispanic origin.Google Scholar
- 15.Teresi, J. A., Ocepek-Welikson, K., Kleinman, M., et al. (2009). Analysis of differential item functioning in the depression item bank from the Patient Reported Outcome Measurement Information System (PROMIS): An item response theory approach. Psychology Science Quarterly, 51(2), 148–180.PubMedGoogle Scholar
- 17.Rivers, D. (2006). Sample matching: representative sampling from Internet panels. Palo Alto, CA: Polimetrix, Inc.Google Scholar
- 24.MPlus: Muthen & Muthen. www.statmodel.com/.
- 25.Reeve, B. B., Hays, R. D., Bjorner, J. B., Cook, K. F., Crane, P. K., Teresi, J. A., et al. (2007). Psychometric evaluation and calibration of health-related quality of life item banks: plans for the Patient-Reported Outcomes Measurement Information System (PROMIS). Medical Care, 45(5 Suppl 1), 22–31.CrossRefGoogle Scholar
- 27.Du Toit, M. (2003). IRT from Scientific Software International. Chicago, IL: SSI, Inc.Google Scholar
- 28.Choi, S., Gibbons, L., & Crane, P. (2011). Lordif: An R package for detecting differential item functioning using iterative hybrid ordinal logistic regression/item response theory and Monte Carlo simulations. Journal of Statistical Software, 39(8).Google Scholar