When should the physical and mental summary scales from the SF-36® or SF-12® be used?
The summary scales for the SF-36® and SF-12® Health Surveys are recommended when: (a) there is a need to limit the number of outcomes being analyzed; (b) a general effect (across sub-scales) in the physical or mental health domain is expected. Because the physical component summary (PCS) and mental component summary (MCS) each measure hundreds of levels of health and extend the range of measurement to higher and/or lower levels than the eight sub-scales, individuals rarely score at the very top or very bottom of the PCS or MCS scales; this is a major advantage. In cases where summary measures are appropriate, the choice between the 36-item or 12-item versions is largely practical and depends on study objectives. The SF-12® reproduces the SF-36® summary scales (PCS and MCS) very well and it is much shorter. The SF-36® profile has the advantage of providing more information about the nature of differences in physical and mental health outcomes. Some medical conditions and most treatments
