Motivation in health behavior: measurement, antecedents, and correlates.

Additional reliability, validity, and information on health behavior correlates for a recently developed measure of intrinsic motivation in health behavior are reported. A randomly selected sample of 379 elders responded to a structured interview containing the Health Self-determinism Index (HSDI) and other relevant variables. The overall reliability of the HSDI was supported with an alpha coefficient of 0.78. The multidimensionality of the instrument was reconfirmed through principal components analysis, and factor invariance across study samples was established. The total HSDI and subscale scores were associated with the practice of selected life-style behaviors. The homogeneity of the sample raises significant considerations relative to contextual item sensitivity and sample-induced response tendencies.