Documentation for: 2006-2007 County-to-County Migration Flows
A. File characteristics:
ASCII language
Filenames = countyinflow0607.dat (for in-migration flows, all states)
countyoutflow0607.dat (for out-migration flows, all states)
Record length = 82 characters
B. Records Included for In-Migration Flows:
The file contains records for the county level migration flows to each
county in the U.S. (including the District of Columbia) from other counties
in the U.S., from foreign, and for non-migrants. There are 4 foreign
categories included:
1. Puerto Rico
2. Virgin Islands
3. APO/FPO ZIP codes
4. foreign countries
Only those in-migration flows containing 10 or more returns are included.
The other in-migration flows are aggregated into 7 summary categories:
1. other county in-migration flows within the same state
2. other county in-migration flows from another state in
the U.S.
3. other county in-migration flows from another state in
the northeast region in the U.S.
4. other county in-migration flows from another state in
the midwest region in the U.S.
5. other county in-migration flows from another state in
the south region in the U.S.
6. other county in-migration flows from another state in
the west region in the U.S.
7. other county in-migration flows from foreign
If the county in-migration flows for any of the 4 regions are based on less
than 10 returns, then none of the records for the 4 regions are included.
If the "other county in-migration to foreign" is based on less than 10
returns, then the record is not included. If either of the summaries
"other county in-migration flows within the same state" or "other county
in-migration flows to another state in the U.S." contains less than 10
returns then both are excluded.
This means that there are a variable number of in-migration flow records
included for each county, or there may be none.
For each county, there are 5 total records representing the sum of all in-
migration flows from all areas. The 5 total records are always included,
however, the data for these totals may be suppressed. The data are
replaced with the value "-1" if they are based on less than 10 returns.
The 5 total records are:
1. total of all in-migration flows from other counties
in the U.S. and from foreign;
2. total of all in-migration flows from other counties
in the U.S.
3. total of all in-migration flows from other counties
in same state in the U.S.
4. total of all in-migration flows from other counties
in different states in the U.S.
5. total of all in-migration flows from foreign
These total records are also summed up to the state, and to the U.S. and
included on the file.
In addition to the suppression procedures implemented for the county in-
flow data, complimentary suppression has been implemented to prevent the
rederivation of suppressed data from the totals.
C. Record description for In-Migration Flows:
Character Description
Positions
1-2 FIPS State Code for Destination:
00 = U.S. Total
01 to 56 = States in the U.S.
3 Blank
4-6 FIPS County Code for Destination:
000 = U.S. or State Total
001 to 999 = Valid Range
7 Blank
8-9 FIPS State Code for Origin:
01 to 56 = Migration flow
57, 58, 59, 96, 97, 98 = Special valid codes 1/
10 Blank
11-13 FIPS County Code for Origin:
000, 001 to 999 = Valid range 1/
14 Blank
15-16 2-Character State Abbreviation:
For U.S. or State Total records, the field
contains the name for the destination state:
US = U.S total record
AL to WY = States in the U.S.
For County Total records, the field
contains the name for the destination state:
AL to WY = States in the U.S.
For non-migrant 2/ records, the field
contains the name for the destination state:
AL to WY = States in the U.S.
For County-to-County flow records, the field
contains the name for the origin state:
AL to WY = States in the U.S.
FR = Foreign
For flow summary records, the field contains
a special code for the summary level:
SS = Other Flows - Same State
DS = Other Flows - Diff State
FR = Foreign
17 Blank
18-49 County Name:
For the U.S. and state total records, the
field contains the name for the total:
"Total Mig - US & For"
"Total Mig - US"
"Total Mig - Same St"
"Total Mig - Diff St"
"Total Mig - Foreign"
For County Total records, the field
contains the county name of the destination, and
the name for the total concatenated together:
"______Tot Mig-US & For"
"______Tot Mig-US"
"______Tot Mig-Same St"
"______Tot Mig-Diff St"
"______Tot Mig-Foreign"
For non-migrant 2/ records, the field
contains the county name of the destination, and
"Non-migrants" concatenated together:
"______Non-migrants"
For County-to-County flow records, the field
contains the name for the origin county:
"Autauga County", "Baldwin County", etc
"Foreign - Overseas"
"Foreign - Puerto Rico
"Foreign - APO/FPO ZIPs"
"Foreign - Virgin Islands
For flow summary records, the field contains
a special code for the summary level:
"Other Flows - Same State"
"Other Flows - Diff State"
"Other Flows - Northeast"
"Other Flows - Midwest"
"Other Flows - South"
"Other Flows - West"
"Foreign - Other flows"
50 Blank
51-59 Number of Returns
-1 = data value suppressed
10 to 999999999999 = Potential legitimate values
60-70 Number of Exemptions
-1 = data value suppressed
10 to 999999999999 = Potential legitimate values
71-82 Aggregate Adjusted Gross Income (in 1,000s)
-1 = data value suppressed
-99999999999 to 999999999999 = Potential legitimate
values
D. Records Included for Out-Migration Flows:
The file contains records for the county level migration flows from each
county in the U.S. (including the District of Columbia) to other counties
in the U.S., to foreign, and for non-migrants. There are 4 foreign
categories included:
1. Puerto Rico
2. Virgin Islands
3. APO/FPO ZIP codes
4. foreign countries
Only those out-migration flows containing 10 or more returns are included.
The other out-migration flows are aggregated into 7 summary categories:
1. other county out-migration flows within the same state
2. other county out-migration flows to another state in the U.S.
3. other county out-migration flows to another state in the northeast region in the U.S.
4. other county out-migration flows to another state in the midwest
region in the U.S.
5. other county out-migration flows to another state in the south region in the U.S.
6. other county out-migration flows to another state in the west region in the U.S.
7. other county out-migration flows to foreign
If the county out-migration flows for any of the 4 regions is based on less
than 10 returns, then none of the records for the 4 regions are included.
If the "other county out-migration to foreign" is based on less than 10
returns, then the record is not included. If either of the summaries
"other county out-migration flows within the same state" or "other county
out-migration flows to another state in the U.S." contains less than 10
returns then both are excluded.
This means that there are a variable number of out-migration flow records
included for each county, or there may be none.
For each county, there are 5 total records representing the sum of all out-
migration flows to all areas. The 5 total records are always included,
however, the data for these totals may be suppressed. The data are
replaced with the value "-1" if they are based on less than 10 returns.
The 5 total records are:
1. total of all out-migration flows to other counties in the U.S. and to foreign;
2. total of all out-migration flows to other counties in the U.S.
2. total of all out-migration flows to other counties in same state in the U.S.
3. total of all out-migration flows to other counties in different states in the U.S.
5. total of all out-migration flows to foreign
These total records are also summed up to the state, and to the U.S. and
included on the file.
In addition to the suppression procedures implemented for the county out-
flow data, complimentary suppression has been implemented to prevent the
rederivation of suppressed data from the totals.
E. Record description for Out-Migration Flows:
Character Description
Positions
1-2 FIPS State Code for Origin:
00 = U.S. Total
01 to 56 = States in the U.S.
3 Blank
4-6 FIPS County Code for Origin:
000 = U.S. or State Total
001 to 999 = Valid Range
7 Blank
8-9 FIPS State Code for Destination:
01 to 56 = Migration flow
57, 58, 59, 96, 97, 98 = Special valid codes 1/
10 Blank
11-13 FIPS County Code for Destination:
000, 001 to 999 = Valid range 1/
14 Blank
15-16 2-Character State Abbreviation:
For U.S. or State Total records, the field
contains the name for the origin state:
US = U.S total record
AL to WY = States in the U.S.
For County Total records, the field
contains the name for the origin state:
AL to WY = States in the U.S.
For non-migrant 2/ records, the field
contains the name for the origin state:
AL to WY = States in the U.S.
For County-to-County flow records, the field
contains the name for the destination state:
AL to WY = States in the U.S.
FR = Foreign
For flow summary records, the field contains
a special code for the summary level:
SS = Other Flows - Same State
DS = Other Flows - Diff State
FR = Foreign
17 Blank
18-49 County Name:
For the U.S. and state total records, the
field contains the name for the total:
"Total Mig - US & For"
"Total Mig - US"
"Total Mig - Same St"
"Total Mig - Diff St"
"Total Mig - Foreign"
For County Total records, the field
contains the county name of the origin, and
the name for the total concatenated together:
"______Tot Mig-US & For"
"______Tot Mig-US"
"______Tot Mig-Same St"
"______Tot Mig-Diff St"
"______Tot Mig-Foreign"
For non-migrant 2/ records, the field
contains the county name of the origin, and
"Non-migrants" concatenated together:
"______Non-migrants"
For County-to-County flow records, the field
contains the name for the destination county:
"Autauga County", "Baldwin County", etc
"Foreign - Overseas"
"Foreign - Puerto Rico
"Foreign - APO/FPO ZIPs"
"Foreign - Virgin Islands
For flow summary records, the field contains
a special code for the summary level:
"Other Flows - Same State"
"Other Flows - Diff State"
"Other Flows - Northeast"
"Other Flows - Midwest"
"Other Flows - South"
"Other Flows - West"
"Foreign - Other flows"
50 Blank
51-59 Number of Returns
-1 = data value suppressed
10 to 999999999999 = Potential legitimate values
60-70 Number of Exemptions
-1 = data value suppressed
10 to 999999999999 = Potential legitimate values
71-82 Aggregate Adjusted Gross Income (in 1,000s)
-1 = data value suppressed
-99999999999 to 999999999999 = Potential legitimate
values
F. Notes:
1. There are special state/county codes created in the processing of the
county-to-county flows files. They are:
State State County
Abbrev Code Code
"Total Mig - US & For" US 96 000
"Total Mig - US" US 97 000
"Total Mig - Same St" US 97 001
"Total Mig - Diff St" US 97 003
"Total Mig - Foreign" US 98 000
"Foreign - Overseas" FR 57 001
"Foreign - Puerto Rico FR 57 003
"Foreign - APO/FPO ZIPs" FR 57 005
"Foreign - Virgin Islands FR 57 007
"Other Flows - Same State" SS 58 000
"Other Flows - Diff State" DS 59 000
"Other Flows - Northeast" DS 59 001
"Other Flows - Midwest" DS 59 003
"Other Flows - South" DS 59 005
"Other Flows - West" DS 59 007
"Foreign - Other flows" FR 57 009
2. Records where the origin state/county code and the destination state/
county code are the same are for the county non-migrant records.