Abstract
The objective of the study was to translate and adapt the SF-36 Health Survey for use in Tanzania and to test the psychometric properties of the Kiswahili SF-36. A cross-sectional study was conducted as part of a household survey of a representative sample of the adult population of Dar es Salaam, Tanzania. The IQOLA method of forward and backward translation was used to translate the SF-36 into Kiswahili. The translated questionnaire was administered by trained interviewers to 3,802 adults (50% women, mean (SD) age 31 (13) years, 50% married and 60% with primary education). Data quality and psychometric assumptions underlying the scoring of the eight SF-36 scales were evaluated for the entire sample and separately for the least educated subgroup (n=402), using multitrait scaling analysis. Forward and backward translation procedures resulted in a Kiswahili SF-36 that was considered conceptually equivalent to the US English SF-36. Data quality was excellent: only 1.2% of respondents were excluded because they answered less than half of the items for one or more scales; ninety percent of respondents answered mutually exclusive items consistently. Median item–scale correlations across the eight scales ranged from 0.47 to 0.81 for the entire sample. Median scaling success rates were 100% (range 87.5–100.0). The median internal consistency reliability of the eight scales for the entire sample was 0.81 (range 0.70–0.92). Floor effects were low and ceiling effects were high on five of the eight scales. Results for n=402 people without formal education did not differ substantially from those of the entire sample. The results of data quality and psychometric tests support the scoring of the eight scales using standard scoring algorithms. The Kiswahili translation of the SF-36 may be useful in estimating the health of people in Dar es Salaam. Evidence for the validity of the SF-36 for use in Tanzania needs to be accumulated.
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References
Ware JE. The status of health assessment 1994. Annu Rev Public Health 1995; 16: 327–354.
Patrick DL, Erickson P. Health Status and Health Policy.Quality of Life in Health Care Evaluation and Resource Allocation. New York: Oxford University Press, 1993.
Spilker B, ed. Quality of Life and Pharmacoeconomics in Clinical Trials. Philadelphia: Lippincott-Raven Publishers, 1996.
Ware JE, Sherbourne CD. The MOS 36-item Short-Form Health Survey (SF-36): I. Conceptual framework and item selection. Med Care 1992; 30: 473–483.
Ware JE, Snow KK, Kosinski M, Gandek B. SF-36 Health Survey Manual and Interpretation Guide. Boston, MA: The Health Institute, New England Medical Center, 1993.
Ware JE, Gandek BL, Keller SD, the IQOLA Project Group. Evaluating instruments used cross-nationally: methods from the IQOLA Project. In: Spiker B, ed. Quality of Life and Pharmacoeconomics in Clinical Trials, 2nd edn. Philadelphia: Lippincott-Raven Publishers, 1996.
Ware JE, Kosinski M, Keller SD. SF-36 Physical and Mental Health Summary Scales-a Users' Manual. Boston, MA: New England Medical Center, The Health Institute, 1994.
Murray CJL, Lopez AD, eds. The Global Burden of Disease. AComprehensive Assessment of Mortality and Disability from Diseases, Injuries, and Risk Factors in 1990 and Projected to 2020. Boston, MA: Harvard School of Public Health, 1996.
Desjarlais R, Eisenberg L, Good B, Kleinman A. World Mental Health.Problems and Priorities in Low-income Countries. New York: Oxford University Press, 1995.
United Republic of Tanzania. Strategic Health Plan 1995–1998. Ministry of Health, Health Sector Reform Group, United Republic of Tanzania, 1995.
Wyss K, Whiting D, Kilima P et al. Utilisation of government and private health services in Dar es Salaam. E Afr Medical J 1996; 73(6): 357–363.
United Republic of Tanzania. Policy Implications of Adult Morbidity and Mortality.End of Phase 1 Report. Dar es Salaam: Ministry of Health, 1997.
Wyss K, Wagner AK, Whiting D et al. Validation of the Kiswahili version of the SF-36 Health Survey in a representative sample of an urban population in Tanzania. Qual Life Res 1998; 7: 111–120.
McHorney CA, Ware JE, Lu JFR, Sherborne CD. The MOS 36-Item Short-Form Health Survey (SF-36): III. Tests of data quality, scaling assumptions, and reliability across diverse patient groups. Med Care 1994; 32: 40–66.
Ware JE, Harris WJ, Gandek B, Rogers B, Reese PR. MAPR for Windows: Multitrait/Multi-item Analysis Program. Boston, MA: Health Assessment Lab, 1997.
Nunnally JC, Bernstein IR. Psychometric Theory, 3rd edn. New York: McGraw-Hill, 1994.
Hays RD, Hayashi T, Carson S, Ware JE. User's Guide for the Multitrait Analysis Program (MAP). Santa Monica, CA: RAND Corporation, 1988.
Wagner AK, Gandek B, Ware JE, with the IQOLA Project Group. SF-36 Health Survey.Handbook for IQOLA Project Investigators. Boston: Health Assessment Lab, 1997.
Sullivan M, Karlsson J, Ware JE. The Swedish SF-36 Health Survey: I. Evaluation of data quality, scaling assumptions, reliability and construct validity across general populations in Sweden. Soc Sci Med 1995; 41(10): 1349–1358.
Ware JE, Keller SD, Gandek B. Evaluating translations of health status questionnaires. Int J Technol Assess Health Care 1995; 11: 525–551.
Cronbach LJ. Coefficient alpha and the internal structure of tests. Psychometrika 1951; 16: 297–334.
Anderson RT, Aaronson NK, Leplège AP, Wilkin D. International use and application of generic quality of life instruments. In: </del>Spilker B, ed. Quality of Life and Pharmacoeconomics in Clinical Trials, 2nd edn. Philadelphia: Lippincott-Raven Publishers, 1996.
Bullinger M, Power MJ, Aaronson NK, Cella DF, Anderson RT. Creating and evaluating cross-cultural instruments. In: Spilker B, ed. Quality of Life and Pharmacoeconomics in Clinical Trials, 2nd edn. Philadelphia: Lippincott-Raven Publishes, 1996.
Sullivan M, Karlsson J, Ware JE. SF-36 Hälsoenkät: Svensk Manual och Tolningsguide (Swedish Manual and Interpretation Guide). Gothenburg: Sahlgrenska University Hospital, 1994.
McHorney CA, Kosinski M, Ware JE. Comparisons of the costs and quality of norms for the SF-36 Health Survey collected by mail versus telephone interview: results from a national survey. Med Care 1994; 32: 551–567.
Perkins JJ, Sanson-Fisher RW. An examination of selfand telephone-administered modes of administration for the Australian SF-36.J Clin Epidemiol 1998;51: 969–973.
The World Bank. World Development Report 1993. Oxford: Oxford University Press, 1993.
Raczek AE, Ware JE, Bjorner JB, et al. Comparison of Rasch and Summated rating scales constructed from SF-36 physical functioning items in seven countries: Results from the IQOLA Project. J Clin Epidemiol 1998; 51: 1203–1214.
Bjoerner J, Ware JE. Using modern psychometric methods to measure health outcomes. Monitor (a publication for members of Medical Outcomes Trust) 1998; 3: 12–16.
Ware JE, Kosinski M. SF-36 Health Survey (Version 2. 0) Technical Note. Boston, MA: The Health Institute, 1996.
Kazis LE, Clark J, Miller DR et al. Amodified version of a short-form health survey for assessing health-related quality of life in veterans: The Veterans Health Study. In: AHSR & FHSR, eds. Health Services Research: Implications for Policy, Management and Clinical Practice. Abstract book of the 11th Annual Meeting, San Diego, CA, 12–14 June 1994: 14–15.
Wagner AK, Keller SD, Kosinski M et al. Advances in methods for assessing the impact of epilepsy and antiepileptic drug therapy on patients' health-related quality of life. Qual Life Res 1995; 4: 115–134.
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Wagner, A.K., Wyss, K., Gandek, B. et al. A Kiswahili version of the SF-36 Health Survey for use in Tanzania: translation and tests of scaling assumptions. Qual Life Res 8, 101–110 (1999). https://doi.org/10.1023/A:1026441415079
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DOI: https://doi.org/10.1023/A:1026441415079