{"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.","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. For collapsed brackets this is the Census sqrt-sum-of-squares approximation over member-cell MOEs (non-integer float, not rounded); the 'all' row carries the published MOE directly. 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) - either the 'all' row's own MOE or a 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 are the Census sqrt-sum-of-squares approximation over member-cell MOEs (non-integer, served as a float; the 'all' row carries the published MOE directly). 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":[],"values_endpoint":"/api/v1/census/population_by_age/values"}