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Data Dictionary

Author Last Updated
Eric Robsky Huntley, PhD August 8, 2024

Coordinate Reference System

For any spatial tables listed below (indicated using 🌐), data is stored in NAD83 / Massachusetts Mainland (ftUS), EPSG:2249.

Output Tables

sites

Residential properties Each row represents a property in the assessors table.

Field Type Description
id (PK) Integer Unique identifier.
fy Integer Fiscal year of assessor's database.
muni_id (FK to munis) String Identifier of property municipality.
ls_date Date Last sale date. Unmodified from MassGIS, see their documentation.
ls_price Integer Last sale price. Unmodified from MassGIS, see their documentation.
bld_area Integer Building area. Unmodified from MassGIS, see their documentation.
res_area Integer Residential area. Unmodified from MassGIS, see their documentation.
units Integer Estimated unit count. For use codes that are tied to specific unit counts, assigns these counts. For others, estimates based on 1) number of addresses on the parcel and 2) residential area,
lnd_val Integer Land value. Unmodified from MassGIS, see their documentation.
bld_val Integer Building value. Unmodified from MassGIS, see their documentation.
use_code Character Use code. Unmodified from MassGIS, see their documentation.
luc Character Land use code. Assigned based on our modified version of a crosswalk supplied by MAPC.
ooc Boolean Owner occupied. If TRUE, listed owner address matches listed property address.
condo Boolean Condo. If TRUE, there are properties with a condo land use code on the parcel (which leads us to treat the whole thing as a 'condo', i.e., a parcel with multiple associated properties).
addr_id (FK to addresses) Integer Identifier of property's listed address.

owners

Each row represents either a unique owner name-address pair.

Field Type Description
id (PK) Integer Unique identifier.
name String Name of un-deduplicated owner.
inst Boolean Institutional owner. If TRUE, we flagged the owner as institutional using keywords unlikely to be identified with individuals.
trust Boolean Trust. If TRUE, we flagged the owner as a trust using keywords.
trustees Boolean Trustees. If TRUE, we flagged the owner as trustees of a trust using keywords.
addr_id (FK to addresses) Integer Identifier of owner address.
company_id (FK to companies) Integer Identifier of company, if we were able to match the owner to a company in the OpenCorporates table.
cosine_group (FK to metacorps_cosine) String Identifier of cosine-deduplicated metacorp. Group assigned by cosine deduplication process.
network_group (FK to metacorps_network) String Identifier of network-deduplicated metacorp. Group assigned by either network deduplication process or cosine deduplication process, when there are no network matches.

sites_to_owners

Represents the many-to-many relationship between owners and sites. All many-to-many relations are induced by splitting non-institutional owners on instances of the word "and" to identify multiple individual owners of a site.

Field Type Description
id (PK) Integer Unique identifier.
site_id (FK to site``) Integer Identifier of property.
owner_id (FK to owners) Integer Identifier of owner.
cosine_group (FK to metacorps_cosine) String Identifier of cosine-deduplicated metacorp. Group assigned by cosine deduplication process.
network_group (FK to metacorps_network) String Identifier of network-deduplicated metacorp. Group assigned by either network deduplication process or cosine deduplication process, when there are no network matches.

companies

Companies from OpenCorporates matched to at least one row in the assessors table, or present in the networks of those companies.

Field Type Description
id (PK) Integer Unique identifier.
name String Name of company.
company_type String Type of company, given by OpenCorporates.
addr_id (FK to addresses) String Identifier of address.
network_id (FK to metacorps_network) String Identifier of network-deduplicated metacorp.

officers

Each row represents a unique name-company relationship.

Field Type Description
id (PK) Integer Unique identifier.
name String Name of officer.
positions String Comma-separated list of positions held by officer in company.
company_id (FK to companies) String Identifier of company.
addr_id (FK to addresses) String Identifier of address.
network_id (FK to metacorps_network) String Identifier of network-deduplicated metacorp.

Summary Fields

Currently included only when load_results() is run with summarize=TRUE.

Field Type Description
innetwork_company_count Integer Number of companies the given officer is an officer of within the network metacorp.

metacorps_network

Each row represents a network-identified 'metacorp', or group of companies that we've identified as related.

Field Type Description
id (PK) Integer Unique identifier.
name String Most common company name within metacorp.

Summary Fields

Currently included only when load_results() is run with summarize=TRUE.

Field Type Description
prop_count Integer Number of properties (i.e., sites rows) linked to a given metacorp.
unit_count Numeric Estimated number of units linked to a given metacorp.
area Integer Summed building area held by a particular metacorp (where 'building area' means the larger of res_area and bld_area).
val Integer Summed building and residential value held by a particular metacorp.
units_per_prop Numeric Total estimated units divided by the property count. This is a measure of what scale of property a given owner invests in.
val_per_prop Numeric Total value divided by property count. A measure of how valuable a given metacorps properties are.
val_per_area Numeric Value per square foot. Another measure of how valuable a metacorps properties are.
company_count Integer How many unique companies appear within a given metacorp.

metacorps_cosine

Each row represents a cosine-deduplication-identified 'metacorp', or group of companies that we've identified as related.

Field Type Description
id (PK) Integer Unique identifier.
name String Most common company name within metacorp.

Summary Fields

Currently included only when load_results() is run with summarize=TRUE.

Field Type Description
prop_count Integer Number of properties (i.e., sites rows) linked to a given metacorp.
unit_count Numeric Estimated number of units linked to a given metacorp.
area Integer Summed building area held by a particular metacorp (where 'building area' means the larger of res_area and bld_area).
val Integer Summed building and residential value held by a particular metacorp.
units_per_prop Numeric Total estimated units divided by the property count. This is a measure of what scale of property a given owner invests in.
val_per_prop Numeric Total value divided by property count. A measure of how valuable a given metacorps properties are.
val_per_area Numeric Value per square foot. Another measure of how valuable a metacorps properties are.

parcels_point (🌐)

Each row is a POINT() representation of a parcel in the MassGIS parcels database.

Field Type Description
loc_id (PK) Integer Unique identifier.
muni_id (FK to munis) String Unique identifier of municipality.
block_group_id (FK to block_groups) String Unique identifier of block group that contains parcel.
tract_id (FK to tracts) String Unique identifier of census tract that contains tract.
geometry Point Geometry Point representation of parcel, found using sf::st_point_on_surface().

addresses

Each row is a unique address (including parsed ranges) found in any of assessors, sites, owners, companies, or owners. Constructed, in part, using the statewide and Boston address layers as a reference dataset.

Field Type Description
id (PK) Integer Unique identifier.
addr String Complete number, street name, type string, often reconstructed from address ranges, PO Boxes, etc.
start Number For ranges, start of address range. For single-number addresses, that single number.
end Number For ranges, end of address range. For single-number addresses, that single number.
body String Street name and address type.
even Boolean Whether an address is even or odd.
muni String Name of municipality.
postal String Postal code. For US addresses, a ZIP code.
state String State (or, for international addresses, a region).
loc_id (FK to parcels_point) String Unique identifier of parcel.

Boundaries

These are loaded using load_results() if load_boundaries = TRUE.

munis (🌐)

Field Type Description
muni_id (PK) Integer Unique identifier.
muni String Name of municipality.
hns Boolean If TRUE, municipality is one of the Healthy Neighborhoods Study areas.
mapc Boolean If TRUE, municipality is part of the MAPC region.
geometry Geometry (MultiPolygon) Municipal boundary.

block_groups (🌐)

Each row is a Massachusetts block group from the most recent vintage available in tigris. Currently, 2022.

Field Type Description
id (PK) String Unique identifier (i.e., the 12-digit GEOID).
geometry Geometry (MultiPolygon) Block group boundary.

tracts (🌐)

Each row is a Massachusetts census tract from the most recent vintage available in tigris. Currently, 2022.

Field Type Description
id (PK) String Unique identifier (i.e., the 11-digit GEOID).
geometry Geometry (MultiPolygon) Block group boundary.

zips (🌐)

Each row is a ZIP code boundary some of which intersects with Massachusetts. (ZIPS can cross state lines).

Field Type Description
zip (PK) String Unique identifier (i.e., the 11-digit GEOID).
geometry Geometry (MultiPolygon) Block group boundary.