RAND SF-12 Health Survey (SF-12)

Introduction:

Health-related quality of life (HRQoL) captures how physical, emotional, and social factors influence everyday functioning and well-being beyond simple disease counts. The RAND SF-12 condenses the classic 36-item survey into 12 carefully chosen questions covering eight domains, giving a reliable snapshot of overall health status that researchers, clinicians, and individuals can track over time.

This tool guides you through each item with a responsive interface, converts raw choices into linear 0–100 scores for every domain, and renders the results on an interactive radar and bar charting layer. A final mean score summarises your profile, and a compact share code lets you revisit or discuss outcomes without exporting personal data.

Use it to monitor rehabilitation progress, measure the impact of lifestyle changes, or prepare focused questions for upcoming medical appointments. Because the SF-12 is a self-report screening instrument, treat scores as guidance rather than diagnosis, and always combine them with professional advice from qualified practitioners. Results do not constitute a clinical diagnosis.

Technical Details:

Concept Overview

The SF-12 operationalises HRQoL by translating twelve Likert-scale responses into eight conceptual domains: General Health, Physical Functioning, Role-Physical, Pain, Role-Emotional, Emotional Well-being, Energy / Fatigue, and Social Functioning. Each answer is linearly transformed onto a 0–100 continuum where 0 denotes maximum limitation and 100 denotes no limitation. Domain means offer population-normed comparisons; their grand mean delivers a concise overall score.

Core Equation

Variables: r – raw response value; n – number of response categories; reverse-scored items substitute (n - r) for (r - 1). The domain score is the arithmetic mean of its transformed items; the overall mean is the average of the eight domain scores.

Interpretation Bands

Scores enable quick visual triage; consecutive assessments highlight trends more reliably than single measurements.

Key Parameters

• r – raw answer (integer 1–6).
• n – total response categories for that item.
• reverse – true when higher raw values indicate poorer health.

Assumptions & Limitations

• Linear scaling assumes equal perceived distance between response options.
• Normative comparisons require age-matched population data.
• Self-report bias can inflate or deflate true health status.
• Single administration cannot capture acute day-to-day variability.

Edge Cases & Error Sources

• Unanswered items yield domain scores of 0, lowering the overall mean.
• All answers identical (extremes) compress result interpretation.
• Reverse-scoring flag mis-set produces inverted domain meanings.
• Repeated retakes within hours may reflect mood, not genuine change.

Scientific Validity

Derived from Ware et al. (1996) and Kazis et al. (2004), the SF-12 shows high correlation with the longer SF-36 and demonstrates acceptable test–retest reliability across diverse populations.

This computation uses only client-side resources; no personal data leaves your browser, supporting GDPR and HIPAA privacy principles.

Step-by-Step Guide:

Follow these steps to receive your personalised SF-12 profile.

1. Click Start Survey.
2. Select one response for each of the 12 items.
3. Watch the progress indicator move toward 100 %.
4. View your eight-domain chart and mean score immediately after the last answer.
5. Copy or bookmark the share code to revisit your results later.

FAQ:

Glossary:

HRQoL

Health-related quality of life.

Raw Score

Original numeric value selected by the user.

Transformed Score

Linear 0–100 value after scaling.

Domain

One of eight SF-12 health dimensions.

Mean Score

Average of multiple transformed scores.