Cody’s Data Cleaning Techniques Using SAS® Software

Introduction

What is data cleaning? In this book, we define data cleaning to include:

• Making sure that the raw data were accurately entered into a computer readable file.

• Checking that character variables contain only valid values.

• Checking that numeric values are within predetermined ranges.

• Checking if there are missing values for variables where complete data is necessary.

• Checking for and eliminating duplicate data entries.

• Checking for uniqueness of certain values, such as patient ID’s.

• Checking for invalid date values.

• Checking that an ID number is present in each of “n” files.

• Verifying that more complex multi-file rules have been followed. For example, if an adverse event of type X occurs in one data set, you expect an observation with the same ...