Telephone vs. mail survey gives different SF-36 quality-of-life scores among cancer survivors

OBJECTIVE: To assess whether SF-36 quality-of-life (QOL) subscale scores varied across two survey modes controlling for cancer type and diagnosis cohort. STUDY DESIGN AND SETTING: Stratified random samples of 720 cancer survivors from six cancer types and three time-since diagnosis cohorts were selected from two state cancer registries. Selected survivors were randomly assigned to mail, telephone, or choice of these for survey administration. This study analyzes completed questionnaires obtained from 140 and 155 survivors who were assigned to telephone and mail, respectively. RESULTS: A significant multivariate effect for survey mode was noted. Mean levels for each subscale controlling for age and accounting for cancer type were higher for telephone compared to mail respondents; significant differences were noted for vitality, role physical, and mental health. The impact of cancer type on QOL subscales was not significant, and the effect of mode was consistent across cancer type. CONCLUSIONS: Previous findings in mode effects for the SF-36 are reproduced here among cancer survivors who may feel more comfortable revealing physical and emotional deficits via mail rather than by telephone. For cancer survivors, it may be that "social desirability" favors responses implying more functioning be it perceived, mental, or physical.     

Measuring Stroke Impact with SIS: Construct Validity of SIS Telephone Administration

Objectives: The purpose of this study was to examine the construct validity of the Stroke Impact Scale (SIS) using telephone mode of administration. Methods: Stroke patients were identified using national VA administrative data and ICD-9 codes in 13 participating VA hospitals. Stroke was confirmed by reviewing electronic medical records. Patients were administered SIS by telephone at 12-weeks post-stroke, and administered the Functional Independence Measure (FIM) and SF-36V at 16 weeks post-stroke. The instrument’s convergent validity and its ability to differentiate between groups of stroke patients with different disability levels were examined using Pearson’s correlations and Kruskal–Wallis one way ANOVA tests. Results: All the relevant relationships yielded high correlation coefficients with statistical significance: 0.86 for FIM-motor vs. SIS-ADL, and 0.77 for PF in SF-36V vs. SIS-PHYSICAL. The SIS presented better score discrimination and distribution for different severity of stroke than FIM and SF-36V without severe ceiling and floor effects. Kruskal–Wallis tests showed the Physical Component Score of SF-36V did not discriminate any disability levels. Physical functioning (PF) in SF-36V, FIM-motor, SIS-PHYSICAL, SIS-16, and SIS-ADL showed better discrimination in person’s functioning. The pairwise comparisons showed that SIS-PHYSICAL, SIS-16, and SIS-ADL discriminated more Rankin levels than FIM-motor and PF in SF-36V. Conclusions: SIS telephone survey had superior convergent validity and was better at differentiating between groups of stroke patients with different disability levels than the FIM and SF-36V with no evidence of ceiling and floor effects. Telephone administration of SIS would be a useful and cost-effective method to follow-up community dwelling veterans with stroke.     

Reliability and validity of the Norwegian version of the Functional Outcomes of Sleep Questionnaire

The aim of this study was to validate the Norwegian version of a self-administered 30-item quality of life questionnaire designed to assess disorders of excessive sleepiness, the Functional Outcomes of Sleep Questionnaire (FOSQ). In total 226 patients previously evaluated for obstructive sleep apnea were included in the study. The patients received a postal questionnaire with the FOSQ, the Short Form 36 (SF-36) questionnaire, and a scale for assessment of excessive daytime sleepiness, the Epworth sleepiness scale (ESS). Among the 178 respondents, all five subscales of the FOSQ showed good internal consistency reliability (Cronbach's alpha = 0.84-0.93). Test-retest on average 18 days apart was satisfactory with intraclass correlation coefficients ranging from 0.61 to 0.86. The pattern of Spearman's rank correlation coefficients between FOSQ scales and related and unrelated scales SF-36 scales gave support to the construct validity of the FOSQ. In conclusion, the Norwegian translation of the FOSQ showed satisfactory internal consistency reliability, test-retest reliability and construct validity, in line with the original version.     

Effects of Mode and Order of Administration on Generic Health-Related Quality of Life Scores

ObjectiveWe evaluate the effects of mode and order of administration on health-related quality of life (HRQOL) scores.MethodWe analyzed HRQOL data from the Clinical Outcomes and Measurement of Health Study (COMHS). In COMHS, we enrolled patients with heart failure or cataracts at three sites (University of California, San Diego, University of California, Los Angeles, and University of Wisconsin). Patients completed self-administered HRQOL instruments at baseline and months 1 and 6 post-baseline, including the EuroQol (EQ-5D), Health Utilities Index (HUI), Quality of Well-Being Scale—self-administered (QWB-SA), and the Short Form (SF)-36v2. At the 6 months follow-up, individuals were randomized to mail or telephone administration first, followed by the other mode of administration. We used repeated measures mixed effects models, adjusting for site, patient age, education, gender, and race.ResultsIncluded were 121 individuals entering a heart failure program and 326 individuals scheduled for cataract surgery who completed the survey by mail or phone at the 6-month follow-up. The majority of the sample was female (53%) and white (86%). About a quarter of the sample had high school education or less (26%). The average age was 66 (36–91 range). HRQOL scores were higher (more positive) for phone administration following mail administration. The largest differences in scores between phone and mail responses occurred for comparisons of telephone responses for those who were randomized to a mail survey first compared with mail responses for those randomized to a telephone survey first (i.e., mode effects for responses that were given on the second administration of the HRQOL measures). The QWB-SA was the only measure that did not display the pattern of mode effects. The biggest differences between modes were 4 points on the SF-36v2 physical health and mental health component summary scores, 0.06 on the SF-6D, 0.03 on the QWB-SA, 0.08 on the EQ-5D, 0.04 on the HUI2, and 0.10 on the HUI3.ConclusionsTelephone administration yields significantly more positive HRQOL scores for all of the generic HRQOL measures except for the QWB-SA. The magnitude of effects was clearly important, with some differences as large as a half-standard deviation. These findings confirm the importance of considering mode of administration when interpreting HRQOL scores.     

Nutrition screen showed good agreement when self- and interviewer administered

OBJECTIVE: SCREEN II is a valid and reliable (test-retest and interrater) nutrition risk-screening index for community-living older adults (50+ years). This questionnaire is preferably self-administered but can be administered by the interviewer for frailer adults who require assistance. Intermode agreement is necessary to determine if mode of administration is interchangeable. STUDY DESIGN AND SETTING: One hundred and thirty-four older adults completed the 17-item questionnaire twice within a 2-week interval in random order; 98 complete questionnaires were available for full analysis. Interviewer administration was completed over the telephone. Intraclass correlation and kappa coefficients were calculated to determine agreement. RESULTS: There is very good agreement between overall self- and telephone-administered SCREEN II scores (intraclass correlation coefficient=0.74). When using a cut-point (score <50) to identify those at risk of malnutrition, agreement is good (kappa=0.53). Increasing age appears to consistently affect agreement. Individual questions which had poorer agreement included: food/fluid intake questions, supplement use, and intention to change weight. CONCLUSION: The self- and interviewer-administered SCREEN II can be used interchangeably in practice or research, if total scores or the risk cutoff are used. Comparison of individual questions completed in different modes is not recommended.     

Transculturally adapted Spanish SRI questionnaire for home mechanically ventilated patients was viable, valid, and reliable

OBJECTIVE: To validate the Spanish Severe Respiratory Insufficiency (SRI) questionnaire, the first health-related quality-of-life questionnaire specific for patients receiving home mechanical ventilation (HMV). STUDY DESIGN AND SETTING: This multicenter prospective study enrolled 115 patients (53 males, age 62+/-13 years) receiving HMV, recruited from five hospitals. Patients were scheduled for two visits during which sociodemographic and clinical data were recorded, and both the Spanish SRI and the SF-36 questionnaires were administered. Viability was assessed by recording timing and the response rate in the questionnaire. Reliability was assessed using intraclass correlation coefficient (ICC) and Cronbach alpha coefficient. Validity was studied by factor analysis, by a correlation test between the SRI and SF-36 questionnaires, and by establishing several simple, plausible, ad hoc hypotheses. RESULTS: The SRI was administered in 10+/-5minutes with >/=96% responses for most items. Cronbach alpha coefficient was >0.7 for all scales except social relationships. ICCs were above 0.8 for all scales. Criterion validity obtained high correlations with SF-36, especially in psychosocial well-being and physical functioning scales. Factor analysis explained 60% of the variability. All ad hoc hypotheses were fulfilled. CONCLUSION: The Spanish version of the SRI questionnaire has good psychometric properties, similar to those of the original questionnaire.     

Telephone administration of the SF-36 health survey: validation studies and population norms for adults in Queensland

Abstract: The Rand Corporation medical outcomes short-form 36 health survey (SF-36) is a multidimensional measure of self-perceived general health status, which has been validated in adult populations in the United States and Great Britain, and, more recently, in an Australian population. The SF-36 is increasingly being used in health outcomes research internationally, mainly as a self-administered tool, and clearly has potential for use in Australia. This study aimed to assess the acceptability, reliability and validity of telephone administration of the instrument in the Queensland adult population, and to provide reliable population norms. We report the results of a telephone survey in which we interviewed 12 793 adults. It was the first large-scale, statewide application of the SF-36 in Australia. A response rate of 82 per cent was achieved, and the SF-36 satisfied psychometric criteria for reliability and construct validity. Population norms broken down by age and sex are provided. They will be important for the interpretation of future studies using the SF-36 in particular population or patient groups.     

Measurement equivalence using a mixed-mode approach to administer health-related quality of life instruments

Purpose

To evaluate the effects of mode, order of administration, and the interaction of mode and order on health-related quality of life scales when self-administered by mixed mode (paper-mode and web-mode) for measurement equivalence.

Methods

Health-related quality of life data was analyzed from the Cancer of the Prostate Strategic Urologic Research Endeavor using the Medical Outcomes Study (MOS) Short Form-36 (SF-36) and the University of California Los Angeles Prostate Cancer Index (UCLA-PCI). A randomized crossover design assigned participants to two groups with a preferred 2–5-day washout period. Cognitive debriefing evaluated participants’ mode preference.

Results

Of the 245 men enrolled, 85 % completed both modes. The majority were White (97 %), college educated (66 %), reported an annual income >$75,000 (46 %), and a median age of 69 years. Intraclass correlation coefficients were high for each item on both instruments (r = .54–.97). Exact percentage agreement for yes/no items was high (≥.88). For the SF-36, significant differences were observed for order of administration (physical component and physical function scores) and for the interaction between mode and order (mental component, role emotional, social function, vitality, and mental health scores). For the UCLA-PCI, the largest difference was 12.8 points lower for sexual bother for order of administration by web-mode first (p = .03). Seventy percent preferred the web-mode, 21 % had no preference, and 9 % preferred the paper-mode.

Conclusion

Web-mode and paper-mode administrations of the SF-36 and UCLA-PCI are equivalent in men with prostate cancer, implying that mixed-mode survey administration is warranted.     

Differences in mail and telephone responses to self-rated health: use of multiple imputation in correcting for response bias

OBJECTIVES: To estimate differences in self-rated health by mode of administration and to assess the value of multiple imputation to make self-rated health comparable for telephone and mail. METHODS: In 1996, Survey 1 of the Australian Longitudinal Study on Women's Health was answered by mail. In 1998, 706 and 11,595 mid-age women answered Survey 2 by telephone and mail respectively. Self-rated health was measured by the physical and mental health scores of the SF-36. Mean change in SF-36 scores between Surveys 1 and 2 were compared for telephone and mail respondents to Survey 2, before and after adjustment for sociodemographic and health characteristics. Missing values and SF-36 scores for telephone respondents at Survey 2 were imputed from SF-36 mail responses and telephone and mail responses to sociodemographic and health questions. RESULTS: At Survey 2, self-rated health improved for telephone respondents but not mail respondents. After adjustment, mean changes in physical health and mental health scores remained higher (0.4 and 1.6 respectively) for telephone respondents compared with mail respondents (-1.2 and 0.1 respectively). Multiple imputation yielded adjusted changes in SF-36 scores that were similar for telephone and mail respondents. CONCLUSIONS AND IMPLICATIONS: The effect of mode of administration on the change in mental health is important given that a difference of two points in SF-36 scores is accepted as clinically meaningful. Health evaluators should be aware of and adjust for the effects of mode of administration on self-rated health. Multiple imputation is one method that may be used to adjust SF-36 scores for mode of administration bias.     

Does electronic implementation of questionnaires used in asthma alter responses compared to paper implementation?

BACKGROUND: Electronic implementation of questionnaires has many advantages, but there may be concerns that it alters versions that were validated on paper. OBJECTIVE: To determine whether electronic implementation alters responses to the SF-36 and asthma quality of life questionnaire (AQLQ), compared to paper implementation. METHODS: Patients with asthma presenting to a pneumologist were asked for consent to participate. Each patient completed both forms of each questionnaire. The order of presentation was alternated sequentially, with the first patient completing the electronic version first. Each patient waited at least 2 hours between completions to minimize recollection of answers. For both the SF-36 and AQLQ, intraclass correlations coefficients were calculated to compare patients' scores, for each scale and overall, on the electronic and paper versions. RESULTS: Sixty-eight patients (mean age: 48 years, 50 females) of 311 contacted were enrolled. Overall intraclass correlation coefficients for the SF-36 and AQLQ were excellent (0.965 and 0.991 respectively). For paper versions, eight questions (AQLQ) and 24 (SF-36) were left blank and nine questions (SF-36) were answered incorrectly by patients selecting more than one answer. Electronic data for one patient could not be retrieved. CONCLUSION: Collecting SF-36 and AQLQ data electronically can decrease the number of spoiled responses without altering the results. Successful implementation depends on proper instruction of the respondent in the handling of the electronic instrument.     

Chinese SF-36 Health Survey: translation,cultural adaptation,validation, and normalisation

STUDY OBJECTIVE: To develop a self administered Chinese (mainland) version of the Short-Form Health Survey (SF-36) for use in health related quality of life measurements in China. DESIGN: A three stage protocol was followed including translation, tests of scaling construction and scoring assumptions, validation, and normalisation. SETTING: 1000 households in 18 communities of Hangzhou. PARTICIPANTS: 1688 respondents recruited by multi-stage mixed sampling. Main results: The assumption of equal intervals was violated for the vitality and mental health scales. The recoded item values were used to calculate scale scores. The clustering and ordering of item means was the same as that of the source and other two Chinese versions. The items in each scale had similar standard deviations except those in the physical functioning, boduily pain, social functioning scales. The item hypothesised scale correlations were identical for all except the social functioning and vitality scales. Convergent validity and discriminant validity were satisfactory for all except the social functioning scale. Cronbach's alpha coefficients ranged from 0.72 to 0.88 except 0.39 for the social functioning scale and 0.66 for the vitality scale. Two weeks test-retest reliability coefficients ranged from 0.66 to 0.94. Factor analysis identified two principal components explaining 56.3% of the total variance. The Chinese SF-36 could distinguish known groups. CONCLUSIONS: This study suggested that the Chinese (mainland) version of the SF-36 functioned in the general population of Hangzhou, China quite similarly to the original American population tested. Caution is recommended in the interpretation of the social functioning and vitality scales pending further studies.     

Measuring quality of life in women with vertebral fractures due to osteoporosis: A comparison of the OQLQ and QUALEFFO

INTRODUCTION: Studies comparing the performance of health-related quality of life instruments in osteoporosis are lacking. We compared the feasibility, validity and reliability of the osteoporosis quality of life questionnaire (OQLQ) and the QUALEFFO (test version) in women with vertebral deformities due to osteoporosis. METHODS: Three hundred and thirty-eight patients diagnosed with primary osteoporosis and vertebral deformity and a random sample of 304 women from the general population (control group) were recruited. Patients and controls were randomly assigned to receive either the OQLQ or the QUALEFFO, and the SF-36 and EQ-5D. Test-retest reliability was assessed in the patient group. RESULTS: The QUALEFFO had more items with missing data and took slightly longer to administer (20.7 vs. 18.7 min). Cronbach's alpha and intraclass correlation coefficient (ICC) values for OQLQ domains (alpha: 0.75-0.91; ICC: 0.85-0.93) were slightly higher than for the QUALEFFO (alpha: 0.63-0.90; and ICC: 0.80-0.93). OQLQ and QUALEFFO domain scores correlated as expected with SF-36 and EQ-5D domains. Both questionnaires discriminated between patients and controls though the OQLQ showed slightly better discriminant power. DISCUSSION: The superior performance of the OQLQ in terms of administration time, missing responses, and discriminatory capacity needs to be weighed against the advantages of using a self-administered instrument such as the QUALEFFO. A full comparison also requires data on sensitivity to change.     

Evaluation of a measurement strategy for Parkinson's disease: Assessing patient health-related quality of life

This study evaluated the feasibility and psychometric properties of self-completed and telephone interview versions of a patient health-related quality-of-life (HQL) questionnaire for Parkinson's disease that included the SF-36 Health Survey (SF-36), the Parkinson's Disease Questionnaire (PDQ-39), and the Medical Outcomes Study Sexual Function Survey. Parkinson's disease patients (n = 150) completed the questionnaire twice: once at the study site and once over the telephone in a randomized order. Ninety-four percent of enrolled patients completed the first HQL assessment and 88% completed both assessments. Cronbach's exceeded 0.70 for all scales except for the self-completed PDQ-39 Social Support subscale (0.57) and the telephone interview PDQ-39 Social Support (0.60) and Cognitions (0.67) subscales and the SF-36 General Health (0.60) and Social Function (0.61) subscales. There were no statistically significant differences in mean HQL scale scores across the two modes of administration. Mean scores for 3 of the PDQ-39 subscales and the Summary Index were significantly poorer (p < 0.05) for patients at later clinical stages. Similarly, patients with dyskinesias reported significantly poorer scores for 4 of the PDQ-39 subscales and the Summary Index and patients with self-reported comorbidities reported poorer SF-36 Physical Function and General Health subscale scores than patients without dyskinesias and comorbidities, respectively. This study suggests that the self-completed and telephone interview versions of the patient HQL questionnaire are feasible and valid for future clinical trial applications.     

Erfassung der gesundheitsbezogenen Lebensqualität mit dem deutschen SF-8

Within a comprehensive comparison of telephone and postal survey methods the SF-8 was applied to assess adult's health-related quality of life. The 1690 subjects were randomly assigned to a telephone survey and a postal survey. Comparisons across the different modes of administration addressed the response rates, central tendency, deviation, ceiling and floor effects observed in the SF-8 scores as well as the inter-item correlation. The importance of age and gender as moderating factors was investigated. Results indicate no or small statistically significant differences in the responses to the SF-8 depending on the actual mode of administration and the health aspect questioned. It was concluded that further investigations should focus on the exact nature of these deviations and try to generate correction factors.     

DDQ-15 Health-Related Quality of Life Instrument for Patients with Digestive Disorders

Objective: This study assessed the reproducibility, reliability, and validity of the DDQ-15, a 15-item quality of life questionnaire for patients with digestive disorders (Phases I and II). It also assessed the reliability of two modes of administration of the instrument: paper versus computer (Phase III). Data Sources/Study Setting: Digestive Disease Center (DDC) patients at the Medical University of South Carolina participated in the study. These patients were attending the DDC on an outpatient basis for a pancreatobiliary disorder, GI cancer, a luminal GI disorder, or liver disorder. Study Design: Over 200 patients participated in the validation study (Phase II) of the DDQ-15. They completed the instrument three times: within one week before a scheduled clinic visit, at the clinic visit, and approximately two months after the clinic visit. The patients also completed the SF-36 and Gastrointestinal Quality of Life Index during the clinic visit. For Phase III, 150 participants were randomized to take the DDQ-15 on computer first or on paper fist. All participants took both versions during the same clinic visit and prior to being seen by a physician. Data Collection Methods: Patients responded to the DDQ-15 items directly on the personal computer for the computer version. The paper version was self-administered by the patients, or if they could not read, the responses on the paper version required manual data entry by the study staff. Principal Findings: For the validation study (Phase II) Cronbach's alpha for the DDQ-15 was 0.92 indicating high internal consistency of the instrument. The intraclass correlation coefficient between pre-clinic and clinic visit scores was 0.97. Pearson's correlation coefficient between the clinic visit DDQ-15 and the Gastrointestinal Quality of Life Index was 0.84, and the coefficients between DDQ-15 and the subscales of SF-36 ranged from 0.55 to 0.79. For Phase III, high internal consistency was observed for both versions, and reproducibility analysis yielded excellent agreement between the two. Intraclass correlation scores indicated high concordance of DDQ-15 scores. Education level and the order in which the two versions were completed were significant factors affecting the concordance of responses. Conclusions: DDQ-15 was shown to be a reliable, reproducible, and valid instrument for assessing QOL in patients with digestive diseases. The simplicity of the instrument should facilitate its use in an ordinary clinical setting. The study also showed that agreement between computer and paper DDQ-15 versions was excellent, indicating that mode of administration minimally affected response to QOL items. This study showed the computer interface to be a reliable alternative to the conventional paper questionnaire.     

Mode of questionnaire administration can have serious effects on data quality

BACKGROUND: One of the main primary data collection instruments in social, health and epidemiological research is the survey questionnaire. Modes of data collection by questionnaire differ in several ways, including the method of contacting respondents, the medium of delivering the questionnaire to respondents, and the administration of the questions. These are likely to have different effects on the quality of the data collected. METHODS: This paper is based on a narrative review of systematic and non-systematic searches of the literature on the effects of mode of questionnaire administration on data quality. RESULTS: Within different modes of questionnaire administration, there were many documented potential, biasing influences on the responses obtained. These were greatest between different types of mode (e.g. self-administered versus interview modes), rather than within modes. It can be difficult to separate out the effects of the different influences, at different levels. CONCLUSIONS: The biasing effects of mode of questionnaire administration has important implications for research methodology, the validity of the results of research, and for the soundness of public policy developed from evidence using questionnaire-based research. All users of questionnaires need to be aware of these potential effects on their data.     

Assessing the validity of the SF-36 General Health Survey

Our objective was to assess the validity of the SF-36 General Health Survey against the Social Maladjustment Schedule (SMS) and two questionnaire measures, the Social Problem Questionnaire and the Nottingham Health Profile (NHP) in a random subsample of 206 men and women from the Whitehall II study, a longitudinal survey of health and disease amongst 10,308 London-based civil servants. We found that social functioning on the SF-36 correlated significantly with social contacts, total satisfaction and total management scores on the SMS, and social isolation and emotional reactions on the NHP. General mental health on the SF-36 was associated with marriage, social contacts, leisure scores, total satisfaction and total management scores on the SMS, and emotional reactions, energy level and social isolation on the NHP. Conversely, physical functioning and physical role limitations were generally not associated with the SMS but were associated with physical abilities and pain on the NHP. In conclusion, this study offers evidence of the discriminant validity of the general mental health and physical functioning scales of the SF-36. We also found moderate construct and criterion validity for the social functioning scale of the SF-36 and considerable overlap between the general mental health and social functioning scales.     

The impact of socioeconomic status on health functioning as assessed by the SF-36 questionnaire: the Whitehall II Study.

OBJECTIVES: This study measured the association between socioeconomic status and the eight scale scores of the Medical Outcomes Study short form 36 (SF-36) general health survey in the Whitehall II study of British civil servants. It also assessed, for the physical functioning scale, whether this association was independent of disease. METHODS: A questionnaire containing the SF-36 was administered at the third phase of the study to 5766 men and 2589 women aged 39 through 63 years. Socioeconomic status was measured by means of six levels of employment grades. RESULTS: There were significant improvements with age in general mental health, role-emotional, vitality, and social functioning scale scores. In men, all the scales except vitality showed significant age-adjusted gradients across the employment grades (lower grades, worse health). Among women, a similar relationship was found for the physical functioning, pain, and social functioning scales. For physical functioning, the effect of grade was found in those with and without disease. CONCLUSIONS: Low socioeconomic status was associated with poor health functioning, and the effect sizes were comparable to those for some clinical conditions. For physical functioning, this association may act both via and independently of disease.     

The rand 36-item health survey 1.0

Recently, Ware and Sherbourne¹ published a new short-form health survey, the MOS 36-Item Short-Form Health Survey (SF-36), consisting of 36 items included in long-form measures developed for the Medical Outcomes Study. The SF-36 taps eight health concepts: physical functioning, bodily pain, role limitations due to physical health problems, role limitations due to personal or emotional problems, general mental health, social functioning, energy/fatigue, and general health perceptions. It also includes a single item that provides an indication of perceived change in health. The SF-36 items and scoring rules are distributed by MOS Trust, Inc. Strict adherence to item wording and scoring recommendations is required in order to use the SF-36 trademark. The RAND 36-Item Health Survey 1.0 (distributed by RAND) includes the same items as those in the SF-36, but the recommended scoring algorithm is somewhat different from that of the SF-36. Scoring differences are discussed here and new T-scores are presented for the 8 multi-item scales and two factor analytically-derived physical and mental health composite scores.     

Reliability and construct validity of the SF-36 in Turkish cancer patients

In this study, we assessed the reliability and construct validity of the SF-36, Turkish version on 419 cancer patients. Cronbach’s α coefficients surpassed the 0.70 criterions for all subscales indicating good internal consistency. Results of the test–retest method showed that the stability coefficients for the eight subscales of the SF-36 ranged between 0.81 and 0.94. Principal components factor analysis with varimax rotation confirmed the presence of seven factors in the SF-36: physical functioning, role limitations due to physical and emotional problems, mental health, general health perception, bodily pain, social functioning, and vitality. In conclusion, the Turkish version of the SF-36 is a suitable instrument that could be employed in cancer research in Turkey.