Factor invariance and the Life Satisfaction Index.

This investigation of the Life Satisfaction Index (LSI) supports findings by Hoyt and Creech (1983) that indicate Adams' (1969) proposed factor structure is not invariant across groups. Two reduced factor models, proposed by Hoyt and Creech and based on a subset of LSI items, were studied with our sample (two levels each of income and age, N = 791). Our work confirms that the Hoyt and Creech 8-item LSI reveals the more stable factor structure of those examined. In addition, we found that the 8-item index has adequate statistical power to be of benefit to those investigators looking at quantitative differences in life satisfaction, with reasonable assurance that older and/or higher-income individuals are interpreting the items in similar ways.