{"main_topic":"census","sub_topic":"acs","topic":"population_by_age","key":"census/acs/population_by_age","version":"1.0.0","year_min":2020,"year_max":2024,"year_gaps":[],"update_frequency":"annual","detail_levels":["counties","districts","states","tracts"],"default_detail":"counties","path_template":"census/population_by_age/year={year}/{detail}.parquet","grain":["year","county_fips","district_code","tract_geoid","age_bracket"],"title":"Population by Age Group (ACS)","summary":"How many people live in each Georgia community, broken down into six age groups - American Community Survey 5-year estimates down to the census-tract level.","description":"Population counts by age group from the American Community Survey 5-year estimates (detailed table B01001, Sex by Age), for Georgia at state, county, school district, and census tract geography, vintages 2020-2024. The 46 sex-by-age cells are collapsed into six school-age-aware brackets (summed over sex - no sex split is served) that are mutually exclusive and sum exactly to the total.","explorer":true,"source":"U.S. Census Bureau, American Community Survey 5-Year Estimates","source_url":"https://data.census.gov/table/ACSDT5Y2024.B01001?g=040XX00US13","endpoint":"/api/v1/census/population_by_age","columns":[{"name":"year","type":"integer","role":"year","nullable":false,"label":"Year","short_description":"","description":"ACS 5-year vintage END year: 2024 covers the pooled 2020-2024 survey period. Consecutive vintages overlap.","valid_values":null,"example":2024,"unit":null,"value_min":null,"value_max":null,"null_meaning":null,"key_metric_grain_contributor":false,"metric_component":null},{"name":"county_fips","type":"string","role":"fk_county","nullable":true,"label":"County FIPS","short_description":"","description":"5-digit county FIPS code (state 13 + county). Populated only on county-level rows.","valid_values":null,"example":"13121","unit":null,"value_min":null,"value_max":null,"null_meaning":null,"key_metric_grain_contributor":false,"metric_component":null},{"name":"district_code","type":"string","role":"fk_district","nullable":true,"label":"District Code","short_description":"","description":"GCD school district code (FK to the education districts dimension). Populated only on district-level rows - Census unified-school-district estimates mapped onto the ~180 standard districts via the dimension's district_census_id.","valid_values":null,"example":"660","unit":null,"value_min":null,"value_max":null,"null_meaning":null,"key_metric_grain_contributor":false,"metric_component":null},{"name":"tract_geoid","type":"string","role":"fk_tract","nullable":true,"label":"Tract GEOID","short_description":"","description":"11-digit census tract GEOID (2020 boundaries). Populated only on tract-level rows.","valid_values":null,"example":"13121011100","unit":null,"value_min":null,"value_max":null,"null_meaning":null,"key_metric_grain_contributor":false,"metric_component":null},{"name":"age_bracket","type":"string","role":"categorical","nullable":false,"label":"Age Bracket","short_description":"","description":"Age group, collapsed from the B01001 sex-by-age cells (summed over sex): under_5, 5_17 (school age), 18_24, 25_44, 45_64, 65_plus; 'all' is the total population. The six brackets are mutually exclusive and sum exactly to 'all'.","valid_values":["18_24","25_44","45_64","5_17","65_plus","all","under_5"],"example":"5_17","unit":null,"value_min":null,"value_max":null,"null_meaning":null,"key_metric_grain_contributor":true,"metric_component":null},{"name":"population_count","type":"integer","role":"metric","nullable":true,"label":"Population Count","short_description":"Estimated residents in the age group.","description":"ACS 5-year estimate of the number of residents in the age bracket: the sum of the bracket's male + female B01001 cells ('all' is the published total). Survey estimate, not a full count - see population_count_moe.","valid_values":null,"example":3394,"unit":"count","value_min":null,"value_max":null,"null_meaning":null,"key_metric_grain_contributor":false,"metric_component":null},{"name":"population_count_moe","type":"number","role":"metric","nullable":true,"label":"Population Count Moe","short_description":"","description":"90 percent margin of error for population_count. under_5, 18_24 and 65_plus carry the Census's published margin from subject table S0101; the 'all' row carries B01001's published MOE; 5_17, 25_44 and 45_64 carry the Census sqrt-sum-of-squares approximation over member-cell MOEs (non-integer float, not rounded; conservative at county level). Never the headline metric.","valid_values":null,"example":null,"unit":"count","value_min":null,"value_max":null,"null_meaning":"Controlled estimate: the value is fixed to official population totals, so the Census publishes no sampling error (annotation -555555555 in the source) - the 'all' row's own MOE, S0101's margin for under_5 / 18_24 / 65_plus, or a summed bracket containing at least one controlled member cell.","key_metric_grain_contributor":false,"metric_component":null}],"key_metric":"population_count","usage":"Star-schema fact table. Join the districts dimension on district_code; the counties dimension on county_fips; the tracts dimension on tract_geoid. Read directly with DuckDB over Parquet.","limitations":"Age brackets are collapsed from the B01001 sex-by-age cells summed over sex - no sex split is served. The six non-'all' brackets are mutually exclusive and sum exactly to the 'all' row. Bracket margins of error: under_5, 18_24 and 65_plus carry the Census's own published margin from subject table S0101 (Age and Sex), whose estimate equals the bracket count; the 'all' row carries B01001's published MOE; 5_17, 25_44 and 45_64, which S0101 does not publish, carry the Census sqrt-sum-of-squares approximation over member-cell MOEs, counting only the largest margin among cells estimated at zero (a non-integer float). That approximation ignores the correlation the Census's population controls create between the detailed cells, so at county level those three brackets' margins can be several times wider than the true margin (they are close at tract level); treat them as conservative. A NULL population_count_moe next to a present estimate means a controlled estimate (fixed to official population totals, no sampling error published; annotation -555555555 in the source) - either the 'all' row's own MOE or a bracket with at least one controlled member cell. ACS 5-year period estimates: the year column is the vintage END year and each estimate pools five years of survey responses (2024 = 2020-2024). Consecutive vintages share about 80% of their sample, so the series is heavily smoothed - never difference overlapping vintages as if they were annual change. Estimates are survey-based and carry 90% margins of error (the *_moe columns); tract-level margins can be large relative to the estimate. All levels serve vintages 2020-2024 only, on 2020-vintage tract boundaries. State rows have NULL county_fips, district_code, and tract_geoid; county rows carry only county_fips, district rows only district_code, tract rows only tract_geoid. District rows cover the ~180 standard (city/county) districts only: the Census publishes school-district estimates at unified school district geography, which has no codes for charter schools, RESAs, or state agencies, and its few Census-only districts (e.g. the Fort Stewart military district) have no GCD district code and are dropped.","null_semantics":{"suppressed_to_null":true,"zero_is_real":true},"available_years":[2020,2021,2022,2023,2024],"schema_hash":"44031e6060a33d4ed7c11c5bd524780c58d72ab1a39aa35fad4a12cfa2ffef31","tags":["census","u.s. census bureau, american community survey 5-year estimates","population_by_age"],"granularity_description":"One row per year, county_fips, district_code, tract_geoid, age_bracket (geography columns are NULL at higher aggregation levels).","example_queries":[{"description":"Latest year (2024), counties detail","query":"SELECT * FROM population_by_age WHERE year = 2024 LIMIT 100"},{"description":"District 660 in 2024","query":"SELECT * FROM population_by_age WHERE district_code = '660' AND year = 2024 LIMIT 100"},{"description":"Filter by age_bracket = 5_17","query":"SELECT * FROM population_by_age WHERE age_bracket = '5_17' AND year = 2024 LIMIT 100"}],"foreign_keys":[{"column":"county_fips","target_object":"counties","target_columns":["county_fips"],"attribute_columns_added":["county_name"],"scope":"global"},{"column":"district_code","target_object":"districts","target_columns":["district_code"],"attribute_columns_added":["district_name","district_census_id","district_type"],"scope":"domain"},{"column":"tract_geoid","target_object":"tracts","target_columns":["tract_geoid"],"attribute_columns_added":["tract_name"],"scope":"global"}],"filters":[{"param":"year","kind":"year_exact","type":"integer","multi_value":false,"enum_enforced":false,"values":null},{"param":"year_min","kind":"year_range","type":"integer","multi_value":false,"enum_enforced":false,"values":null},{"param":"year_max","kind":"year_range","type":"integer","multi_value":false,"enum_enforced":false,"values":null},{"param":"detail","kind":"detail","type":"string","multi_value":false,"enum_enforced":true,"values":["counties","districts","states","tracts"],"default":"counties"},{"param":"district_code","kind":"foreign_key","column":"district_code","type":"string","multi_value":true,"enum_enforced":false,"values":null},{"param":"county_fips","kind":"foreign_key","column":"county_fips","type":"string","multi_value":true,"enum_enforced":false,"values":null},{"param":"tract_geoid","kind":"foreign_key","column":"tract_geoid","type":"string","multi_value":true,"enum_enforced":false,"values":null},{"param":"age_bracket","kind":"categorical","column":"age_bracket","type":"string","multi_value":true,"enum_enforced":true,"values":["18_24","25_44","45_64","5_17","65_plus","all","under_5"],"has_total":true,"total_value":"all","requires_single_value":false,"nullable":false,"null_filter_token":null},{"param":"district_type","kind":"dimension_attribute","dimension":"districts","column":"district_type","type":"string","multi_value":true,"enum_enforced":true,"values":["commission_charter","resa","standard","state_agency","state_charter","state_school","state_special"]}],"filter_hints":[],"non_additive":[],"value_implications":[],"year_meaning":null,"pooled_rates":[],"values_endpoint":"/api/v1/census/population_by_age/values"}