A randomized clinical trial compares a new antiarrhythmic drug to placebo in 400 patients with atrial fibrillation. Patients are followed for the occurrence of sudden cardiac death for up to 24 months. During follow-up, 30 patients withdraw consent and are lost to follow-up at various times, 20 die from noncardiac causes, and 50 complete the 24-month period without experiencing sudden cardiac death. In constructing Kaplan-Meier survival curves for time to sudden cardiac death, which statement about censoring is correct?