Codes

This is a 14-digit numeric variable.

Description

PID indicates the person identifier in the original dataset.

Note that in datasets that include more than one diary per person and/or more than one person per household, PID is not unique. Use IDENT to identify uniquely cases and link persons and activities records in hierarchical files.

Comparability

This variable is comparable across years.

Universe

Availability

• 1930, 1965, 1975, 1985, 1993, 1995, 1998, 2003-2012, 2018

Flags