The SF-36v2™, SF-36®, SF-12v2™, SF-12™, and SF-8™ surveys capture
patient-based assessments of eight health domains. While the surveys share many similarities, they are also different in some important ways.
Similarities and differences associated with the following features are reviewed below:
Versions
Content
Recall period
Scoring options
Norms
Translations
Documentation
The implications of these differences, and some guidelines for choosing a survey, are reviewed in the section Which SF Survey To Use.
Versions
The SF-36 and SF-12 are available in original (SF-36 and SF-12) and updated (SF-36v2 and SF-12v2) versions,
while the SF-8 is available in one version only. Although the SF-36v2 and SF-12v2 are very similar to their Version 1.0
counterparts, they offer a number of improvements, including increased range and precision for the role-functioning scales,
improved item wording, and an easier-to-use format. These and other features are highlighted in the following sections.
For more information about the Version 2.0 surveys, click here.
Content
All of the SF surveys measure the same eight domains of health: physical
functioning, role limitations due to physical health (role-physical), bodily
pain, general health perceptions, vitality, social functioning, role limitations
due to emotional problems (role-emotional), and mental health. Because more
items permit better representation of each health domain, the domains are best
represented in the SF-36 (both versions), followed by the SF-12 (both versions),
and the SF-8. The improved question wording and simplified response categories
in the SF-12v2 and SF-36v2 surveys make the revised versions easier to
understand and administer and less culturally biased than the original versions.
The SF-36 and SF-12 have 12 items in common and this comparability was
preserved in the updated versions of these surveys. The SF-8 has only one item
in common with the SF-36 and no items in common with the SF-12. Content is very
similar across all the surveys, however, and measures of corresponding concepts
reflect a high correlation across all forms.
Recall Period
Most of the items in each survey ask respondents to consider a specific period of time, or recall period, when responding.
Versions 1.0 and 2.0 of the SF-36 and SF-12 are available with two recall periods: the standard form of each survey uses a 4-week recall, and the
acute form of each survey uses a 1-week recall period. The SF-8 is available in three different forms, each using a different recall period: the standard form
uses a 4-week recall, the acute form uses a 1-week recall, and a third form uses a 24-hour recall.
Forms using the various recall periods have been validated and normative data are available for each.
Scoring Options
The SF-8 and the original and revised versions of the SF-36 yield scores for eight dimensions of health as well as physical and mental summary scores.
The SF-12v2 also produces both scale and summary scores, an improvement over the original version of the SF-12 which had yielded summary scores only.
Norm-based scoring (NBS) algorithms can be used to score the both versions of the SF-36v2 and SF-12 and the SF-8. NBS represents a significant improvement over the 0 to 100 scoring system that
was originally used with the SF-36. NBS recalibrates and standardizes scale and summary scores to a mean of 50 and a standard deviation of 10 in the 1998 general U.S. population.
Such standardization makes the scores easier to interpret and allows for comparison of scores obtained with different SF surveys.
Norms
Up-to-date norms are available for the standard and acute forms of the SF-36v2, SF-12v2, and SF-8. Norms for the SF-36v2 and the SF-12v2 are based on the 1998 general US population, while the SF-8 norms are based on a 2000 US population sample.
Translations
The SF-36, SF-12, and SF-8 have been translated into more than 50 languages; to see lists of available translations,click here. While the availability of
translations for the original versions offers a noteworthy advantage over the updated versions, adaptations to achieve translations of the SF-36v2 and
SF-12v2 forms are underway in many countries and should be completed by late 2003. For information on translations of the updated versions,
contact license@qualitymetric.com.
Documentation
Up-to-date manuals documenting form development, scoring algorithms, general US population norms, and other interpretation guidelines are available for the SF-36v2, SF-12v2, and SF-8. Supplements are included in the SF-36v2 and SF-12v2 manuals that provide essential information about the original versions of these surveys, including the original scoring chapters and norms.
