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1. Summary levels
You may not realize the significance of these, but we strongly suggest that you do not delete them. The summary level tells you what the record represents and it may help you later if you sort the data. For example, aggregate tract totals are Summary Level 140, but a piece of a census tract inside a city or CDP would be Summary Level 730.
| Summary Code | Description |
| 040 | State total |
| 050 | County totals |
| 155 | City totals |
| 140 | Aggregate census tract totals (if ordered) |
| 080 | Census tracts split by city or CDP boundaries (if ordered) |
| 091 | Block groups split by city or CDP boundaries (if ordered) |
| 150 | Aggregate block groups totals in order by tract number (if ordered) |
2. Census Tracts
Please note that census tracts will have more than one line of data each if they contain more than one city or CDP. For example a census tract can be partly in San Leandro, Hayward, San Lorenzo and unincorporated remainder not assigned to a CDP. Pieces of tracts within each city are in Summary Level 080.
The total of all a census tract's parts is found in summary level 140.
3. Block Groups
Please note that block groups do not
have unique numbers and must be sorted with their census tract
number and their place code. Block groups can also be split between
cities if a place boundary runs through the area. Therefore,
there may be more than record of data for a block group.
- Email us -- || --Return to the Demographics Home PageSite Last Modified: January 17, 1999.