The structure and reliability of health belief indices.

A wealth of research using the Health Belief Model provides empirical evidence of the model's utility in predicting health, illness, and sick role behaviors. Until recently, however, little attention has been paid to the important issues of the validity and reliability of measures used to assess various health belief dimensions. Using factor analysis, our study demonstrates that moderately reliable indices covering a wide spectrum of distinct health beliefs can be constructed and then replicated across independent samples. The factor analysis approach revealed that condition-specific measures of perception of susceptibility and severity and situation-specific measures of perceived barriers are empirically distinct from general measures of these beliefs. We therefore recommend caution in mixing general and specific questionnaire items within the same index when measuring these beliefs. A factor representing perceptions of health threat emerged, but its composition require further clarification. The degree of similarity between the factor structures in the two independent samples provides support for the existence of independent health belief dimensions.