Effective communication is crucial for successful behavior change. However, despite much research in training and development, instructional communication, and public health surrounding communication, it is still unclear what constitutes such effective delivery behaviors, especially for an adult learner population (those over 25 years old). Using cognitive load theory and cognitive-affective theory of learning with media as theoretical frameworks, this dissertation proposes a quality of delivery scale for measuring effective communication across instructional settings with an adult learner audience. Informed by public health, training and organizational communication, as well as adult education and instructional communication, the final valid and reliable QD scale consists of seven communication characteristics that are associated with reduced cognitive load, increased motivation, and increased compliance. Ultimately, this three-phase study consisted of: (a) developing the QD scale, (b) confirming the factor structure, as well as convergent and predictive validity, and (c) testing a theoretical model of QD.