Assessment of a short scale to measure social support among older people

Background: Social support strongly influences health, but research has been limited by the paucity of brief, inexpensive, psychometrically sound scales suitable for use with older people. Method: The validity and reliability of the 11-item Duke Social Support Index (DSSI) were tested among a random sample of 565 community dwelling people aged 70 years and over. Results: A response rate of 76% was obtained. Participants had a mean age of 76 years. Internal consistency using Cronbachs alpha for the overall index was 0.77. Test-retest reliability (n=117) scores ranged from 0.70 to 0.81. Concurrent validity is supported by the DSSI's moderate to strong correlations with the interview Schedule for Social Interaction. Construct validity of the DSSI was supported by moderate correlations with health, quality of life and loneliness. To further test construct validity a multiple regression model was used and 25.6% of the variance in social support was explained using three expected variables; self rated health, quality of life, and living arrangements. Conclusion: Strong evidence for reliability and validity of the 11-item Duke Social Support Index support its use in aged care research and health promotion strategies. Implications: The DSSI provides researchers with the opportunity to use a brief measure of social support which has been assessed specifically with older Australians instead of single-item measures or scales which have limited psychometric evidence.