     Documentation for: 2005-2006 County-to-County Migration Flows


A.  File characteristics:

    CD ROM
    ASCII language
    Filenames = countyin0506.dat (for in-migration flows, all states)
                
                countyout0506.dat (for out-migration flows, all states)

    Record length = 91 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
    is 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 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 diferent 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

       83-91         Median Adjusted Gross Income
                       -1 = data value suppressed or Median AGI < $0
                        0 = Potential legitimate value
                        1 = Median AGI > $100,000
                        2 to 99999 = 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 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.
      3.  total of all out-migration flows to other counties
          in same state in the U.S.
      4.  total of all out-migration flows to other counties
          in diferent 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

       83-91         Median Adjusted Gross Income
                       -1 = data value suppressed or Median AGI < $0
                        0 = Potential legitimate value
                        1 = Median AGI > $100,000
                        2 to 99999 = 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"         TT        96       000
       "Total Mig - US"               TU        97       000
       "Total Mig - Same St"          TS        97       001
       "Total Mig - Diff St"          TD        97       003
       "Total Mig - Foreign"          TF        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.
