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Census 2000 - Types of Census Tract Relationships

Within the population-based and street-side mileage-based census tract relationship files for Census 2000, there are four main types of census tract relationships that occur: no change, merge, revision, and split.

Note: In some instances, various combinations of these four main relationships can exist.

Examples of the four main census tract relationship types are provided below for both the street-side mileage and population-based census tract relationship files for Kent County, Delaware.

1. No Change

This record is an example of a census tract (401) that exhibited no change from 1990 to 2000.

Note: Both percentages are 100-percent and there are no "P" part indicators.

Population-based example:

10001040100    5337100010001040100    53371000    5337    124644DEKent  

Street-side mileage-based example:

10001040100    2036100010001040100    20361000    2036   124644DEKent  

2. Merge

These records show that 1990 census tracts 403 and 404 merged to form 2000 census tract 404.

Note: The effect of rounding shows up in these records. The sum of the population for each record (824 and 823) does not equal the population of the 2000 census tract (1,648). (Refer to the note on rounding in the "File Descriptions" section, under the heading "1. Population-based Census Tract Relationship File.")

Population-based example:

10001040300    172100010001040400P    11560149    172     77556DEKent
10001040400    984100010001040400P    11560851    984    100528DEKent  

Street-side mileage-based example:

10001040300    824100010001040400P    16480500    824     77556DEKent
10001040400    823100010001040400P    16480500    823    100528DEKent 

3. Revision

These records show that 2000 census tract 414 includes a portion of 1990 census tract 415.

Population-based example:

10001041400   3008100010001041400P   30180997   3008   6671DEKent
10001041500P  3799000310001041400P   30180003     10    110DEKent
10001041500P  3799099710001041500    37891000   3789   3068DEKent

Street-side mileage-based example:

10001041400     350100010001041400P    3650958    350    6671DEKent
10001041500P    310004910001041400P    3650042     15     110DEKent
10001041500P    310095110001041500     2941000    294    3068DEKent 

4. Split:

These records show that 1990 census tract 402 split into three 2000 census tracts - - 402.01, 402.02, and 402.03.

Population-based example:

10001040200P    11735029610001040201    34771000    3477     9796DEKent
10001040200P    11735044210001040202    51891000    5189    32059DEKent
10001040200P    11735026210001040203    30691000    3069    59822DEKent

Street-side mileage-based example:

10001040200P    2987021110001040201     6311000     631     9796DEKent
10001040200P    2987036310001040202    10851000    1085    32059DEKent
10001040200P    2987042610001040203    12721000    1272    59822DEKent 

Source: U.S. Census Bureau | Geography | (301) 763-1128 |  Last Revised: July 08, 2013