This research aims to clarify the dimensionality of the Life Satisfaction Index A (LSIA). A multiple indicator structural equation model, which includes eleven items loading on three first-order factors and one second-order factor, is proposed to delineate the structure of LSIA. This model was empirically examined by using data from the 1974 NCOA-Harris survey, "Myths and Realities of Aging in America." The proposed model was supported and consistently replicated across four randomly divided subsamples. (Author)