Table A.1:

Sample Construction and Match Statistics

Panel A. Number of individuals satisfying sample criteria
Meet baseline demographic criteria	27,374,000
and have non-missing PIK	26,253,000
and have unique PIK	26,147,000
and have unique birth county	24,462,000
Panel B. Birth county match type, as percent of total
Exact	76.85
Exact-abbreviation	3.57
Duplicate	10.95
Probabilistic	5.11
Hand check	3.52

Notes: The baseline demographic criteria are having non-allocated values for state of birth, birth year, gender, and race, plus being born in the U.S. according to the Census/ACS survey. A unique PIK is one that does not appear more than once in a survey year. Sample contains individuals born from 1950–1980 who are age 25–64 at the time of the survey.

Source: Confidential 2000–2013 Census/ACS data linked to the SSA NUMIDENT file