<qa>  What is the presumed barrier to treatment intensification for uncontrolled hypertension?A large amount of literature suggests that the majority of uncontrolled hypertensives are under medical care, and that lack of control is largely explained by physicians not intensifying treatment to achieve the BP targets recommended in the national guidelines. Traditional physician education, feedback, and reminders have a limited effect in promoting a rapid rate of guideline implementation. The theoretical framework of diffusion of innovations suggests that providing physicians with tools to reduce uncertainty about the attributes of a guideline may accelerate the adoption process. The presumed barriers to treatment intensification for uncontrolled hypertension are: 1 uncertainty over the patients true BP; 2 uncertainty over whether the patient is adherent to medications already prescribed; and 3 uncertainty over the benefits of adding medications when patients express preference for lifestyle modification. 