12-Item Short Form Survey

How to use our SF-12 template?

Carepatron has created a free template based on the standard SF-12. Follow these steps to get started:

Step 1: Download the SF-12 form

Access the free 12-item short-form health survey by clicking the "Use template" button. This lets you open the template via the Carepatron app, where you can modify it. For a PDF copy, just choose "Download."

Step 2: Give your patient a copy

Hand your patient with a copy of the SF-12 to complete. Explain how the survey will help measure their overall health. Allow them time to work through the questions and provide any assistance they may need.

Step 3: Score their answers

Calculate your patient's score. Higher scores indicate that an individual has fewer limitations in activities of daily living or has greater psychological well-being. Lower scores may indicate a need for further medical intervention or lifestyle changes to improve health outcomes.

Step 4: Provide feedback

After scoring the survey, provide your patient with feedback on their overall health. Discuss any areas of concern and make recommendations for steps they can take to improve their health.

Scoring

Scoring the standard SF-12 involves several steps to ensure accurate and meaningful results. This includes cleaning and recoding item responses, transforming them into indicator variables, applying regression-based weights, and standardizing the final scores. Below is a brief guide on how to score this health survey (Ware et al., 1998):

Data cleaning and item recoding

All 12 items should be checked for out-of-range values before assigning the final item value. Any response lower or higher than the predefined minimum or maximum should be recorded as missing data.

Four items require reverse scoring so that higher values indicate better health. These are general health (GH1), bodily pain (BP2), mental health (MH3), and vitality (VT2). For example, the highest precoded value for “How much of the time did you feel calm and peaceful?” is “6 - None of the time,” which represents a poorer health state and should be reversed.

Creating indicator variables

Each response category, except for the highest health state, is assigned a binary indicator variable (1 = endorsed, 0 = not endorsed). Out of 47 possible response categories, 35 indicator variables are created. This logic applies to all SF-12 items.

Weighting and aggregation of indicator variables

The PCS-12 and MCS-12 scores are calculated using specific regression weights for physical and mental health. The indicator variables are multiplied by these weights, and the products are summed to compute the scores.

The formula for computation is:

• PCS-12 = sum of indicator values × physical regression weights
• MCS-12 = sum of indicator values × mental regression weights

If any SF-12 item is missing, it is recommended that the summary score be set to missing.

Norm-based standardization

Each summary score is transformed into a standardized scale with a mean of 50 and a standard deviation of 10, ensuring comparability with the general U.S. population.

The final scores are computed by adding a norm-based constant to the weighted sum of the indicator variables:

• PCS-12 = (sum of weighted physical scores) + norm-based constant
• MCS-12 = (sum of weighted mental scores) + norm-based constant

Scoring checks

Errors in scoring can lead to inaccurate summary scale scores. It is essential to verify that all item responses fall within the expected range and that indicator variables are correctly coded as either 0 or 1.

Physical health items (PF02, PF04, RP2, RP3, BP2) should have the highest correlation with PCS-12 and the lowest with MCS-12. Conversely, emotional (RE2, RE3) and mental health (MH3, MH4) items should correlate highest with MCS-12 and lowest with PCS-12. General health (GH1) usually correlates higher with MCS-12, while vitality (VT2) aligns more with PCS-12.

A very low correlation between PCS-12 and MCS-12 is expected. Any discrepancies should be investigated for scoring errors.

When to use an SF-12 questionnaire?

The SF-12 is an excellent tool for evaluating overall health. It can be used to monitor changes in health over time and identify areas of improvement or deterioration. You can use this tool to:

Monitor a patient's health over time

You can use the SF-12 to compare results over time and track patient health. This may help identify any underlying problems or improvement areas requiring additional attention.

Assess the health-related quality of life

The SF-12 can help you assess an individual's overall health-related quality of life. It is beneficial when a patient suffers from a chronic condition and needs to make lifestyle changes or explore available treatments.

Screen patients for conditions

This assessment tool quickly provides an overall view of a patient's health. This may help you identify any underlying conditions that require further investigation.

Assess the impact of medical interventions

The SF-12 can be used to evaluate the effectiveness of medical interventions. It can help you determine which treatments most effectively improve a patient's quality of life.

References

Rand Healthcare. (n.d.). 12-Item short form survey from the RAND medical outcomes study. https://www.rand.org/health-care/surveys_tools/mos/12-item-short-form.html

Ware, J. E., Kosinski, M., Keller, S. D., Qualitymetric Incorporated, & New England Medical Center Hospital. Health Assessment Lab. (1998). SF-12: How to score the SF-12 physical and mental health summary scales (Second edition). Qualitymetric Inc.; Boston, Mass.

Ware, J., Kosinski, M., & Keller, S. D. (1996). A 12-item short-form health survey: Construction of scales and preliminary tests of reliability and validity. Medical Care, 34(3), 220–233. https://doi.org/10.1097/00005650-199603000-00003