Variable Types and Formats

There are two basic variable types:

• String. Also referred to alphanumeric. String values can contain any combination of letters, numbers, and other characters.
• Numeric. Numeric values are stored internally as double-precision floating-point numbers.
  Note: SPSS® Statistics can at times process what would normally present as single decimal values as multiple decimal values (up to 15 decimals). For more information, see IBM SPSS Statistics does not consistently process double-precision, floating-point numbers.

Variable formats determine how raw data is read into storage and how values are displayed and written. For example, all dates and times are stored internally as numeric values, but you can use date and time format specifications to both read and display date and time values in standard date and time formats. The following sections provide details on how formats are specified and how those formats affect how data are read, displayed, and written.