Cody's Data Cleaning Techniques Using SAS, Second Edition

3 Checking for Missing Values

Introduction

Inspecting the SAS Log

Using PROC MEANS and PROC FREQ to Count Missing Values

Using DATA Step Approaches to Identify and Count Missing Values

Searching for a Specific Numeric Value

Creating a Macro to Search for Specific Numeric Values

Introduction

Many data sets contain missing values. There are several ways in which missing values can enter a SAS data set. First of all, the raw data value may be missing, either intentionally or accidentally. Next, an invalid raw value can cause a missing SAS value to be created. For example, reading a character value with a numeric informat will generate a missing value. Invalid dates are another common cause of missing values generated by SAS. Finally, many operations, ...