The SHEP is a randomized, placebo-controlled trial that will follow standard clinical trial principles in analyzing data relating to its proposed hypotheses. The protocol has stated a priori the main objective as well as the secondary subgroup hypotheses. Sample size calculations for SHEP have accounted for dropins to and drop-outs from active therapy as well as for the risk of nonstroke death. The sample size achieved (4,736 participants) should be adequate to address the proposed questions. Monitoring procedures have been described and established. A data and safety monitoring board that uses these procedures is closely following the data from the trial. The board will periodically examine the data to determine whether termination of the study is warranted.