Longitudinal Data and SAS

List of Programs

1  The RETAIN Statement

Program 1-1 Demonstrating a DATA Step without a RETAIN Statement

Program 1-2 Demonstrating a DATA Step with a RETAIN Statement

Program 1-3 Demonstrating a DATA Step That Does Not Work without a RETAIN Statement

Program 1-4 Adding a RETAIN Statement to Program 1-3

Program 1-5 Attempting to Generate a Sequential SUBJECT Number without Using a RETAIN Statement

Program 1-6 Adding a RETAIN Statement to Program 1-5

Program 1-7 Demonstrating the SUM Statement

Program 1-8 Demonstrating That Variables from a SET Statement Are Retained

2  The LAG and DIF Functions

Program 2-1 Using the LAG Function to Compare a Value in the Current Observation to One in the Previous Observation

Program 2-2 Demonstrating What Happens ...