The Cronbach’s alpha for internal consistency reliability for the 10 items comprising the BP Knowledge Scale was .90. The alpha scores if items were deleted ranged from .87 to .91 indicating that no single item decreased reliability appreciably. However, the item assessing the role of medications in controlling BP had an item-to-total scale correlation much lower than any other item (r = .36). The item stated: “If I have high blood pressure, the only way to keep my blood pressure within normal limits is to take medications (pills) every day as prescribed by my doctor.” Evaluation of the wording suggested that using the term “only way” to control BP may have been confusing, thus a decision was made to drop this item from the knowledge scale. The alpha for the revised 9-item scale was .91, with the corrected item-to-total correlations ranging from .62 to .80 indicating strong correlations with the total score.
Internal consistency reliability for the 10 items comprising the BP Self-Care Scale was α =.71. Evaluation of the item-to-total correlation revealed a negative correlation (r = −.13) for the item regarding alcohol use. Assessment of the item indicated that, despite no problems in pilot testing, the wording of the item could be confusing, and therefore, it was dropped from the scale. Cronbach’s alpha for the revised 9-item scale was .78, with alphas ranging from .73 to .80 if items were deleted. No further adjustments were made to the BP Self-Care Scale based on these data.