Look Before You Leap - A Technique to Simulate a Look-Ahead Function

In base SAS programming there is a very useful function called LAG which allows a SAS program to reference previous values of a SAS program variable. Wouldn't it be wonderful if a similar function were available to look ahead at the value of a dataset field in the next observation. There is no such function available but with some simple programming logic a "Look ahead" functionality can be achieved. This paper will describe a technique that can be used to achieve this.