# Data dictionary: data.csv for Highland County, Virginia

One row is one figure: a place, a measure, a period, an estimate, its margin of error and where it came from.

## Columns

| Column | Meaning |
|---|---|
| row_id | The key of the row: place level, measure and period, joined by dots. Unique in the file. |
| geo_level | county, state or nation. |
| geo_id | The Census Bureau geographic identifier (GEO_ID) of the place. |
| geo_name | The name of the place as the Census Bureau writes it. |
| measure | The short name of the measure. See the list of measures. |
| label | The measure in words. |
| period | The year or years the figure covers. ACS figures cover five years together, for example 2020-2024. |
| estimate | The figure. Empty when the source publishes none. |
| moe90 | The margin of error at the 90 percent confidence level, in the same unit as the estimate (percentage points for shares). Empty when there is none. |
| moe_status | published: the margin is from the source. derived: calculated for this report from published margins. controlled: the source fixes the figure to a population total, so there is no sampling error. none_published: the source gives no margin for this kind of figure. not_available: no usable margin or no figure. |
| unit | usd (US dollars), percent, count, ratio, index or per_1000. |
| source_id | Which source: acs5_2024, acs5_2019, bps, fhfa_hpi. Two sources joined by + when a figure uses both. |
| source_ref | The table cell or the file the figure came from. |
| derived | yes when the figure was calculated for this report from published figures; no when it is as published. |
| formula | For derived figures, the arithmetic. |
| flag | wide_margin: the margin is at least half the estimate. margin_exceeds_estimate: the margin is as large as the estimate. open_ended_median, no_estimate_published, no_margin_published, no_index_published, not_in_file, input_not_available, zero_base: why a figure or margin is missing. The first two are this report's own reading aid, not a Census Bureau rating. |

## Measures

| Measure | Label | Unit | Definition |
|---|---|---|---|
| population | Population | count | Total population. B01003_001. |
| housing_units | Homes (housing units) | count | All housing units, occupied or vacant. B25001_001. |
| occupied_units | Occupied homes (households) | count | Occupied housing units. B25002_002. |
| vacant_units | Vacant homes | count | Vacant housing units, including seasonal homes. B25002_003. |
| vacancy_share | Share of homes that are vacant | percent | Vacant units as a share of all housing units. Includes homes held for seasonal or occasional use. |
| seasonal_units | Homes for seasonal or occasional use | count | Vacant units for seasonal, recreational or occasional use. B25004_006. |
| seasonal_share | Share of homes for seasonal or occasional use | percent | Seasonal, recreational or occasional-use units as a share of all housing units. |
| owner_units | Owner-occupied homes | count | Owner-occupied housing units. B25003_002. |
| renter_units | Renter-occupied homes | count | Renter-occupied housing units. B25003_003. |
| owner_share | Share of households that own | percent | Owner-occupied units as a share of occupied units. |
| renter_share | Share of households that rent | percent | Renter-occupied units as a share of occupied units. |
| median_home_value | Median home value | usd | Median value of owner-occupied housing units, as estimated by the owner. B25077_001. |
| median_gross_rent | Median gross rent | usd | Median monthly contract rent plus utilities, renter-occupied units paying cash rent. B25064_001. |
| median_household_income | Median household income | usd | Median household income in the past 12 months, in the dollars of the period's last year. B19013_001. |
| median_rent_pct_income | Median gross rent as a share of household income | percent | Median gross rent as a percentage of household income. B25071_001. |
| renter_burden_share | Renters paying 30 percent or more of income on rent | percent | Renter households with gross rent at 30.0 percent or more of household income, as a share of renter households for which the percentage was computed. B25070. |
| renter_severe_burden_share | Renters paying 50 percent or more of income on rent | percent | Renter households with gross rent at 50.0 percent or more of household income, as a share of renter households for which the percentage was computed. B25070. |
| owner_burden_share | Owners paying 30 percent or more of income on housing | percent | Owner households, with or without a mortgage, with selected monthly owner costs at 30.0 percent or more of household income, as a share of owner households for which the percentage was computed. B25091. |
| value_to_income | Median home value divided by median household income | ratio | Median home value divided by median household income for the same place and period. |
| permits_units | Homes authorized by building permits | count | New privately owned housing units authorized by building permits in the year, all structure types, with imputation for offices that did not report. |
| permits_units_1 | Homes authorized, single-family | count | Units in one-unit structures authorized by permits. |
| permits_units_2_4 | Homes authorized, in buildings of two to four homes | count | Units in two-unit and three-to-four-unit structures authorized by permits. |
| permits_units_5plus | Homes authorized, in buildings of five or more homes | count | Units in structures of five or more units authorized by permits. |
| permits_units_reported | Homes authorized, as reported by permit offices | count | Units authorized as reported by permit offices, without imputation. |
| permits_per_1000_homes | Homes authorized per 1,000 existing homes | per_1000 | Homes authorized by permits in the year, divided by the ACS count of housing units, times 1,000. |
| hpi_index | House price index, rebased so 2015 equals 100 | index | FHFA all-transactions house price index, annual, rebased by Seven Sky so that 2015 equals 100. |
| hpi_change_1yr | House price index, change over one year | percent | Annual change in the FHFA all-transactions index, as published by FHFA. |
| hpi_change_5yr | House price index, change over five years | percent | Change in the FHFA all-transactions index over five years, calculated from the published index values. |
| hpi_change_10yr | House price index, change over ten years | percent | Change in the FHFA all-transactions index over ten years, calculated from the published index values. |

## Margin of error arithmetic

- Sum or difference of estimates: the square root of the sum of the squared margins. When several estimates in a sum are zero, only the largest of their margins is counted, once.
- Share (the numerator is part of the base): margin = sqrt(MOE_num^2 - p^2 * MOE_base^2) / base, with p = num / base. If the value under the root is negative, the plus sign is used.
- Ratio (the numerator is not part of the base): margin = sqrt(MOE_num^2 + r^2 * MOE_base^2) / base, with r = num / base.
- Two estimates are called different when the gap between them is wider than sqrt(MOE_a^2 + MOE_b^2).
- These follow the Census Bureau handbook Understanding and Using American Community Survey Data: What All Data Users Need to Know, chapter 8.

## Sources

- ACS 2020-2024: U.S. Census Bureau, American Community Survey 5-Year Estimates, 2020-2024 (table-based summary file). https://www2.census.gov/programs-surveys/acs/summary_file/2024/table-based-SF/
- ACS 2015-2019: U.S. Census Bureau, American Community Survey 5-Year Estimates, 2015-2019 (table-based summary file, prototype). https://www2.census.gov/programs-surveys/acs/summary_file/2019/prototype/
- Building Permits Survey: U.S. Census Bureau, Building Permits Survey, annual county and state files, 2015 to 2025. https://www2.census.gov/econ/bps/
- FHFA HPI: Federal Housing Finance Agency, House Price Index, all-transactions, annual county, state and national files (developmental index). https://www.fhfa.gov/data/hpi/datasets