Acute ischemic stroke is a medical emergency. Early reperfusion therapy can reduce functional disability, and early secondary prevention therapy can reduce early recurrent stroke. The rate of recurrent stroke in the first month is approximately 9.4% (95% CI, 6%-14%) among patients with ischemic stroke caused by large-artery atherosclerosis and approximately 1.2% (95% CI, 0.4%-3.0%) among patients with ischemic stroke caused by intracranial small vessel disease.1 Because some effective early prevention therapies may be risky or costly (eg, carotid revascularization or dual antiplatelet therapy) and some patients have a low risk of recurrent stroke, targeting risky or costly treatments to patients at high risk of recurrent stroke who are most likely to benefit is desirable. However, experienced physicians are unable to accurately discriminate or separate patients with ischemic stroke at high and low risk of recurrent stroke.2 Clinical prediction models, also known as prognostic scores, which combine multiple risk factors to estimate the absolute risk of future stroke, might improve risk prediction. Recent evidence indicates that the ABCD2 score, calculated from 5 clinical features (age, blood pressure, clinical features, duration of transient ischemic attack, and presence of diabetes mellitus), does not reliably discriminate patients at low and high risk,3 and the predictive power of several other prognostic tools is modest.4 More promising are prognostic scores that incorporate information about the nature and activity of the vascular disease causing the index stroke, such as the ABCD3–I score and the Recurrence Risk Estimator (RRE).5-10