Synonyms

Self-assessed overall health; Self-rated health

Definition

The SF-8™ is an abbreviated version of an original 36-item health survey (SF-36 Health Survey). It contains psychometrically based physical and mental health summary measures. The eight domains include general health, physical functioning, role physical, bodily pain, vitality, social functioning, mental health, and role emotional.

Description

SF-8™ is a generic multipurpose short-form health-related quality of life instrument and was developed by the RAND Corporation and the Medical Outcomes Study (MOS) in the 1980s, which was originally a short-form health survey with 36 questions. The SF-8™ was developed primarily for use in large surveys of general and specific populations, for comparing the burden of diseases across different age, disease, and treatment groups. The SF-8™ has been shown to be effective monitoring population health and large-scale outcomes studies. The SF-8™ has been translated in over 30 different languages and is used in many countries (Campolina, Pinheiro, Ciconelli, & Ferraz, 2011; Lefante et al. 2005; Roberts, Browne, Ocaka, Oyok, & Sondorp, 2008; Tokuda et al., 2009; Valles et al., 2010).

Eight questionnaire items (response categories) include:

  • Overall health (six categories: very poor, poor, fair, good, very good, excellent)

  • Physical functioning capacity (five categories: could not do physical activities, quite a lot, somewhat, very little, not at all)

  • Role physical or difficulties with daily work because of physical pain (five categories: could not do daily work, quite a lot, some, a little bit, none at all)

  • Bodily pain (six categories: very severe, severe, moderate, mild, very mild, none)

  • Vitality (five categories: none, a little, some, quite a lot, very much)

  • Social functioning (five categories: not do social activities, quite a lot, moderately, slightly, not at all)

  • Mental health or emotional problems (five categories: extremely, quite a lot, moderately, slightly, not at all)

  • Role emotional or absence from daily activities because of emotional problems (five categories: could not do daily activities, quite a lot, somewhat, very little, not at all)

In addition to the SF-8™ single-item scales, Physical Component Summary (PCS) and Mental Component Summary (MCS) measures are calculated by weighting each SF-8 item using a norm-based scoring method given in the instrument guidelines. Higher summary PCS and MCS scores indicate better health. The physical functioning, role physical, and bodily pain correlate highest with the PCS summary measure, while social functioning, role emotional, and mental health items correlate highest with the MCS summary measure. The correlation between PCS-8 and MCS-8 summary measures is typically lower than 0.30 (Ware, Kosinski, Dewey, & Gandek, 2001).

SF-8™ single-item scales and PCS/MCS measures can be scored on the same metrics as the SF-36 scales and summary measures. The development, validation, and norming of the SF-8™ health survey forms, including standard (4-week recall), acute (1-week recall), and 24-h recall versions, are documented (Ware et al., 2001). SF-8™ scales are scored using norm-based scoring methods (NBS “50/10” referring to means of 50 and standard deviations of 10); means, variances, and regression weights come from studies in the general US population conducted in 2000. The standardization process allows meaningful comparison with other scales.

Validity of the SF-8™ has been reported to be quite high in various settings; among the US population, test-retest reliability for the eight scales ranged from 0.59 to 0.70, and test-retest reliability for PCS-8 and MCS-8 was 0.73 and 0.74, respectively (Ware et al., 2001). Test-retest reliability of the SF-8™ was reported in northern Uganda (n = 1,206); the intraclass correlation results were 0.61 for PCS and 0.68 for MCS showing good agreement over a period of time (Roberts et al., 2008). The Spanish version of the SF-8™ was tested (n = 2,991), and Cronbach’s alpha of 0.92 was reported (Valles et al., 2010). Findings of the SF-8™ from 908 male workers in South Korea reported Cronbach’s alpha of 0.86 (Eum et al., 2007).

Overall the SF-8™ provides a brief and feasible method of measuring general physical and mental health in large population surveys.

Cross-References

Medical Outcomes Study Short-Form 36-Item Questionnaire

Quality of Life (QoL)