Measurement properties and normative data for the Norwegian SF-36: results from a general population survey

Area of Science:

• Health Services Research
• Psychometrics
• Population Health

Background:

• Current interpretation of the SF-36 in Norway relies on 1996 data.
• This study presents updated 2002-2003 general population data for the SF-36.
• The measurement properties of this updated dataset needed assessment.

Purpose of the Study:

• To assess the measurement properties of the Norwegian SF-36 version 1.2 using 2002-2003 general population data.
• To provide updated normative data for the SF-36 in Norway.
• To evaluate the suitability of this data for health services research.

Main Methods:

• A postal survey of 9,164 Norwegians aged 16+ (response rate 58.9%) using the SF-36.
• Assessment of data completeness, item-total correlations, and internal consistency (Cronbach's alpha).
• Analysis of floor and ceiling effects, and generation of normative data by age and gender.

Main Results:

• High data completeness (97.5-99.8%) and scale reliability (Cronbach's alpha > 0.8).
• Item-total correlations generally > 0.4, with expected variations.
• Floor effects were low except for Role-Physical; high ceiling effects observed for Role-Physical and Role-Emotional. Females generally scored lower than males. Younger groups scored higher on physical health aspects; older groups showed varied scores for mental health aspects.

Conclusions:

• The 2002-2003 SF-36 data meet criteria for normative data application.
• This dataset is more recent, larger, and includes more older individuals than the 1996 data.
• The updated data can enhance the interpretation of SF-36 scores in clinical and health services research.