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Codebook for NHGIS data file 'nhgis0731_ts_nominal_state'
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Contents
    - Data Summary
    - Data Dictionary
    - Geographic Integration Methods
    - Source Data
    - Citation and Use
 
Detailed notes on time series design and comparability are available at: 
    https://www.nhgis.org/sites/www.nhgis.org/files/nhgis_time_series_tables.pdf 
 
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Data Summary
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Time series layout:     Time varies by column
Geographic level:       State
Geographic integration: Nominal
Years:                  1790, 1800, 1810, 1820, 1830, 1840, 1850, 1860, 1870, 1880, 1890, 1900, 1910, 1920, 1930, 1940, 1950, 1960, 1970, 1980, 1990, 2000, 2010, 2020
 
Tables:
 
1. Total Population
   Years: 1790, 1800, 1810, 1820, 1830, 1840, 1850, 1860, 1870, 1880, 1890, 1900, 1910, 1920, 1930, 1940, 1950, 1960, 1970, 1980, 1990, 2000, 2010, 2020
   Code:  A00
 
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Data Dictionary
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Context Fields 
        GISJOIN:     GIS Join Match Code
        STATE:       NHGIS Integrated State Name
        STATEFP:     FIPS State Code
        STATENH:     NHGIS Integrated State Code
 
Table 1: (A00) Total Population
    Time series AA: Persons: Total
        A00AA1790:   1790: Persons: Total
        A00AA1800:   1800: Persons: Total
        A00AA1810:   1810: Persons: Total
        A00AA1820:   1820: Persons: Total
        A00AA1830:   1830: Persons: Total
        A00AA1840:   1840: Persons: Total
        A00AA1850:   1850: Persons: Total
        A00AA1860:   1860: Persons: Total
        A00AA1870:   1870: Persons: Total
        A00AA1880:   1880: Persons: Total
        A00AA1890:   1890: Persons: Total
        A00AA1900:   1900: Persons: Total
        A00AA1910:   1910: Persons: Total
        A00AA1920:   1920: Persons: Total
        A00AA1930:   1930: Persons: Total
        A00AA1940:   1940: Persons: Total
        A00AA1950:   1950: Persons: Total
        A00AA1960:   1960: Persons: Total
        A00AA1970:   1970: Persons: Total
        A00AA1980:   1980: Persons: Total
        A00AA1990:   1990: Persons: Total
        A00AA2000:   2000: Persons: Total
        A00AA2010:   2010: Persons: Total
        A00AA2020:   2020: Persons: Total
 
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Geographic Integration Methods
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Nominal Integration:

    Nominally integrated tables link geographic units across time according to
    their names and codes, disregarding any changes in unit boundaries. The
    identified geographic units match those from each census source, so the
    spatial definitions and total number of units may vary from one time to
    another (e.g., a city may annex land, a tract may be split in two, a new
    county may be created, etc.). The tables include data for a particular
    geographic unit only at times when the unit's name or code was in use,
    resulting in truncated time series for some areas.
    
    Users should be cautious when interpreting changes in nominally integrated
    time series because a single unit code may refer to distinctly different
    areas at different times. If you are uncertain whether any boundaries
    changed in your areas of interest, we recommend inspecting NHGIS GIS files
    to confirm. (NHGIS supplies GIS boundary files for all units and years in
    nominally integrated time series *except* 1970 places and county
    subdivisions.)
    
    Alternatively, for some topics and time periods, NHGIS provides
    "geographically standardized" time series, which provide data from multiple
    times for a single census's geographic units (e.g., 2000 and 2010 data for
    2010 census units). A disadvantage of standardized time series is that, in
    areas where source units do not nest perfectly within a unit of the standard
    year (e.g., where a source 2000 unit intersects multiple 2010 units), NHGIS
    applies interpolation to standardize the data, a process which may
    occasionally produce substantial errors.

Complete documentation on time series integration methods is available at:
    https://www.nhgis.org/documentation/time-series
 
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Source Data
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Additional documentation on NHGIS data sources is available at:
    https://www.nhgis.org/documentation/tabular-data

Table 1: (A00) Total Population
 
    Time series AA: Persons: Total
        Year: 1790
            Source dataset: 1790 Census: Population Data [US, States & Counties]
                Source table: NT1. Total Population
                    Universe: Persons
                        Variable: [AAA001] Total
        Year: 1800
            Source dataset: 1800 Census: Population Data [US, States & Counties]
                Source table: NT2. Total Population (from 1900 Census Report)
                    Universe: Persons
                        Variable: [AAU001] Total
        Year: 1810
            Source dataset: 1810 Census: Population Data [US, States & Counties]
                Source table: NT2. Total Population (from 1900 Census Report)
                    Universe: Persons
                        Variable: [AA3001] Total
        Year: 1820
            Source dataset: 1820 Census: Population Data [US, States & Counties]
                Source table: NT9. Total Population
                    Universe: Persons
                        Variable: [ABM001] Total
        Year: 1830
            Source dataset: 1830 Census: Population Data [US, States & Counties]
                Source table: NT1. Total Population
                    Universe: Persons
                        Variable: [ABN001] Total
        Year: 1840
            Source dataset: 1840 Census: Population & Other Data [US, States & Counties]
                Source table: NT1. Total Population
                    Universe: Persons
                        Variable: [ACD001] Total
        Year: 1850
            Source dataset: 1850 Census: Population, Agriculture & Other Data [US, States & Counties]
                Source table: NT1. Total Population
                    Universe: Persons
                        Variable: [ADQ001] Total
        Year: 1860
            Source dataset: 1860 Census: Population, Agriculture & Other Data [US, States & Counties]
                Source table: NT1. Total Population
                    Universe: Persons
                        Variable: [AG3001] Total
        Year: 1870
            Source dataset: 1870 Census: Population, Agriculture & Other Data [US, States & Counties]
                Source table: NT1. Total Population
                    Universe: Persons
                        Variable: [AJ3001] Total
        Year: 1880
            Source dataset: 1880 Census: Population, Agriculture & Other Data [US, States & Counties]
                Source table: NT1. Total Population
                    Universe: Persons
                        Variable: [AOT001] Total
        Year: 1890
            Source dataset: 1890 Census: Population, Housing, Agriculture & Manufacturing Data [US, States & Counties]
                Source table: NT1. Total Population
                    Universe: Persons
                        Variable: [AUM001] Total
        Year: 1900
            Source dataset: 1900 Census: Population, Housing, Agriculture & Manufacturing Data [US, States & Counties]
                Source table: NT1. Total Population
                    Universe: Persons
                        Variable: [AYM001] Total
        Year: 1910
            Source dataset: 1910 Census: Population, Housing & Agriculture Data [US, States & Counties]
                Source table: NT1. Total Population by Year
                    Universe: Persons
                        Variable: [A3Y001] 1910
        Year: 1920
            Source dataset: 1920 Census: Population, Housing, Agriculture & Manufacturing Data [US, States & Counties]
                Source table: NT1. Total Population
                    Universe: Persons
                        Variable: [A7L001] Total
        Year: 1930
            Source dataset: 1930 Census: Population, Agriculture & Economic Data [US, States & Counties]
                Source table: NT1. Total Population
                    Universe: Persons
                        Variable: [BDP001] Total
        Year: 1940
            Source dataset: 1940 Census: Population, Housing, Agriculture & Economic Data [US, States & Counties]
                Source table: NT1. Total Population
                    Universe: Persons
                        Variable: [BV7001] Total
        Year: 1950
            Source dataset: 1950 Census: Population, Housing & Agriculture Data [US, States & Counties]
                Source table: NT1. Population
                    Universe: Persons
                        Variable: [B18001] Total
        Year: 1960
            Source dataset: 1960 Census: Population Data [US, States, Counties]
                Source table: NT1. Total Population
                    Universe: Persons
                        Variable: [B5O001] Total
        Year: 1970
            Source dataset: 1970 Census: Count 4Pa - Sample-Based Population Data
                Source table: NT126. 100% Population
                    Universe: Persons
                        Variable: [C1I001] Total
        Year: 1980
            Source dataset: 1980 Census: STF 1 - 100% Data
                Source table: NT1A. Persons
                    Universe: Persons
                        Variable: [C7L001] Total
        Year: 1990
            Source dataset: 1990 Census: STF 1 - 100% Data
                Source table: NP1. Persons
                    Universe: Persons
                        Variable: [ET1001] Total
        Year: 2000
            Source dataset: 2000 Census: SF 1a - 100% Data [Areas Larger Than Block Groups]
                Source table: NP001A. Total Population
                    Universe: Persons
                        Variable: [FL5001] Total
        Year: 2010
            Source dataset: 2010 Census: SF 1a - P & H Tables [Blocks & Larger Areas]
                Source table: P1. Total Population
                    Universe: Total population
                        Variable: [H7V001] Total
        Year: 2020
            Source dataset: 2020 Census: P.L. 94-171 Redistricting Data Summary File
                Source table: P1. Race
                    Universe: Total population
                        Variable: [U7B001] Total
 
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Citation and Use of NHGIS Data
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        IPUMS National Historical Geographic Information System: Version 17.0 
        [dataset]. Minneapolis, MN: IPUMS. 2022. 
        http://doi.org/10.18128/D050.V17.0

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