The method of systematic random sampling (METHOD=SYS) selects units at a fixed interval throughout the sampling frame or stratum after a random start. PROC SURVEYSELECT chooses the first unit randomly ...

Radiation-Induced Heart Disease After Breast Cancer Treatment: How Big a Problem, and How Much Can—and Should—We Try to Reduce It? Impact of Examined Lymph Node Count on Precise Staging and Long-Term ...