Topic: Data Structure and Variable Preparation

Variable Types and Measurement Scales

Summarizing Missingness Before Preparation

Separating Data Errors from Valid Extremes

Rows, Columns, and Observational Units

Recoding Categories With a Traceable Map

Recognizing Missing-Value Codes

Recording Measurement Units Consistently

Preparing Dates and Elapsed-Time Variables

Preparing Ordered Categories

Managing Category Levels Across Data Subsets