Development of common metrics for donation attitude, subjective norm, perceived behavioral control, and intention for the blood donation context

BACKGROUND: The Theory of Planned Behavior has been widely used in blood donation research, but the lack of uniform, psychometrically sound measures makes it difficult to draw firm conclusions or compare results across studies. Accordingly, the goal of this study was to develop such measures of donation attitude, subjective norm, perceived behavioral control, and intention. STUDY DESIGN AND METHODS: Exploratory and confirmatory factor analyses (CFAs) were conducted on survey responses collected from college students (n = 1080). The resulting scales were then administered to an independent sample of experienced donors (n = 433) for additional CFAs and to test whether the Theory of Planned Behavior model provided a good fit to the data. RESULTS: CFAs conducted on both samples support the use of six-item scales, with two factors each, to measure donation attitude, subjective norm, and perceived behavioral control and a single-factor three-item scale to measure donation intention. Further, structural equation modeling of these measures revealed that the Theory of Planned Behavior provided a strong fit to the data (comparative fit index, 0.976; root mean square error of approximation, 0.041; standardized root mean square residual, 0.055) and accounted for 73.7% of the variance in donation intention. CONCLUSION: The present findings confirm the applicability of the Theory of Planned Behavior to the blood donation context and more importantly provide psychometric support for the future use of four brief measures of donation attitude, subjective norm, perceived behavioral control, and intention.