Tract coverage discrepancy: Why do 1990 and 2000 crosswalks to 2010 tracts produce different numbers of output tracts?

1

Why do my 1990 and 2000 data crosswalks to 2010 census tracts produce different numbers of output tracts (73,057 vs 74,002)? Should they match?
TRACT COVERAGE ANALYSIS

1990 unique tracts: 73057
2000 unique tracts: 74002

Tracts only in 1990: 0
Tracts only in 2000: 945
Tracts in both: 73057

Common tracts across 1990 and 2000: 73057

✗ Different number of tracts: 1990 has 73057, 2000 has 74002
Difference: 945 tracts

2

Hi,

The 1990 to 2010 crosswalk has no records for Puerto Rico, and the 2000 to 2010 does have records for Puerto Rico. So, that will account for the differences in the tract counts.

Sincerely,

Dave Van Riper

IPUMS