Figure 1 presents the proportion of individuals with their blood pressure under control at 6 month and 42 month time periodsaccording to their score on the four-itemmedication-taking scale. At the 6 month interval, a significant relationship was foundbetween these two variables. Individualswho scored high on the scale were morelikely to have their blood pressure undercontrol than those individuals who scoredlow. The point biserial correlation was equalto 0.43 (P < 0.01). This finding reconfirmsthe previously assessed concurrent validityas noted in the baseline needs assessment. 36Analysis of the scale's predictive validity(medication-taking behavior at baseline regressed with blood pressure control levels at42 months) indicates a more pronouncedlinear relationship.