Reliability and validity of the health locus of control scale.

The Multidimensional Health Locus of Control (MHLC) Scale developed by Wallston, Wallston, and De Vellis (1978) was subjected to analysis of its factor structure, internal consistency, test-retest reliability with parallel forms, and predictive validity. The I (internal control of health) and P (powerful others control of health) subscales were found to be moderately homogeneous, and reliable over 7 months, although P rises with age, lower social status, and acute illness. The C (chance control of health) subscale, however, showed little stability over time. No predictive relationships were found between subscale scores and later health, or compliance with medical instructions.