Linking Landlords: An Examination of the Methods and Impacts of Linking Administrative Ownership Data
Forrest Hangen
1966
"Defining the ownership of slum tenements is a far from easy task"
566 Parcels
"Defining the ownership of slum tenements is a far from easy task"
566 Parcels
Developments since 1966
Computational Advances
-
Computing Power -
Text-matching algorithms
-
Digitized Open(ish) Data
Computational Advances
-
Computing Power -
Text-matching algorithms
-
Digitized Open(ish) Data
"Defining the ownership of rental housing is still no easy task!"
-Forrest after reading Sternlieb
Developments since 1966
Computational Advances
-
Computing Power -
Text-matching algorithms
-
Digitized Open(ish) Data
Ownership Obscurity
-
Rise of the LLC
Developments since 1966
AIMS
Accurately link landlords to their properties to Uncover and Quantify the effects of Ownership Obscurity
Data
Property Tax Assessment Records
- Owner's Name
- Owner's Mailing Address
Boston, MA
2004-2019
Corporation Filing Records
- LLC Name
- Individuals' Names
- Individuals' Addresses
Challenges
Messy Data
Intentional Obscurity
Elmer G Gill
Elmr G Gill
Greystone LLC
Eagle LLC
Challenges
Messy Data
Intentional Obscurity
2 Different Solutions
Challenges
Messy Data
Intentional Obscurity
Deliberate Strategy
Limiting Liability
Messy Data
Solution:
1. Text Cleaning and Standardization
L.L.C., Lmtd liability co,llc LLC
Fifty-eight Green Street L.L.C.
58 Green st llc
Fifty-eight Green Street L.L.C.
58 Green st llc
Solution:
1. Text Cleaning and Standardization
L.L.C., Lmtd liability co,llc LLC
Fifty-eight Green Street L.L.C.
58 Green st llc
58 GREEN ST LLC
58 GREEN ST LLC
Messy Data
Solution:
2. Fuzzy Matching
Elmer G Gill Elmr G Gill
Glynn Realty Assoc IV LLC Glynn Realty Association I LLC
1. Text Cleaning and Standardization
L.L.C., Lmtd liability co,llc LLC
Messy Data
Fuzzy Matching
Glynn Realty Assoc IV LLC Glynn Realty Association II LLC
(Probabilistic Matching)
By Hand
( small-scale)
Out-of-the-Box
( Dedupe, OpenRefine, matchit, etc.)
Custom Probabilistic Matching
651,612 owners
Elmer G Gill Elmer H Gill
Custom Probabilistic Matching
Out-of-the-Box
( Dedupe)
Elmer G Gill Elmer H Gill
Pairs of Names
Glenn Ross 87 Blue Ave
Glenn Ross 4 East St
[' Gl','Gly','lyn','ynn','nn ','n R',' Re','Rea','eal','alt','lty','ty ' ...]
3-gram
| " A" | " Ad" | " Al" | " As" | "El " | "Bar" | "Llc" | . . . | |
|---|---|---|---|---|---|---|---|---|
| Glynn Realty Assoc IV LLC | 0 | 0 | 0 | .178 | 0 | 0 | .199 | . . . |
| . . . | . . . | . . . | . . . | . . . | . . . | . . . | . . . | . . . |
tf-idf
Custom Probabilistic Matching
Glynn Realty Assoc IV LLC Glynn Realty Association II LLC
Custom Probabilistic Matching
Glynn Realty Assoc IV LLC Glynn Realty Association II LLC
Cosine Similarity
cos(\theta) = \frac{\sum_{i=1}^{n}{A_{i}B_{i}}}{\sqrt{\sum_{i=1}^{n}{A_{i}^{2}}}\sqrt{\sum_{i=1}^{n}{B_{i}^{2}}}}
measures similarity between two entities using the cosine of the angle between their two vectors in a multidimensional space
Is all this work worth it?
Raw Tax Assessment
Cleaning & Standardization
Fuzzy-Matching
4.8%
7.1%
12.3%
Owners
Raw Tax Assessment
Cleaning & Standardization
Fuzzy-Matching
24.5%
27.8%
33.7%
Units
Greystone LLC
Eagle LLC
Not done yet...
Intentional Obscurity
Greystone LLC
Eagle LLC
Greystone LLC
Eagle LLC
Corporation Filing Records
Intentional Obscurity
Greystone LLC
Eagle LLC
Greystone LLC
Eagle LLC
Corporation Filing Records
Fuzzy Matching
Intentional Obscurity
Intentional Obscurity
Intentional Obscurity
Intentional Obscurity
Intentional Obscurity
55 GREYSTONE LLC
EAGLE LLC
12 GREEN ST LLC
Tax Assessment
55 GREYSTONE LLC
EAGLE LLC
12 GREEN ST LLC
Corporation Records
Tax Assessment
55 GREYSTONE LLC
EAGLE LLC
12 GREEN ST LLC
Greystone Realty Corporation
Unique ID
Tax Assessment
55 GREYSTONE LLC
EAGLE LLC
12 GREEN ST LLC
Unique ID
-
Landlord Size
-
Corporate Status
-
Obscurity
-
Geographic Scope
-
Property Types
-
Property-level Outcomes
Tax Assessment
Raw Tax Assessment
4.8%
Owners
Raw Tax Assessment
Fuzzy-Matching
24.5%
Units
Fuzzy-Matching
12.3%
33.7%
+11.9%
+17.5%
Corporate Data
16.7%
Corporate Data
42.0%
Is all this work worth it?
Is all this work really worth it?
Ok, but ...
YES!
Intentional Obscurity
Consolidation
Herfindahl-Hirschman Index (HHI)
HHI = \sum_{i=1}^{N}{S_i^{2}}
where S = a landlord's share of an outcome
Units
Eviction Filings
Herfindahl-Hirschman Index (HHI)
HHI = .16^{2}+.16^{2}+.16^{2}+.16^{2}+.16^{2}+.16^{2}
HHI =0.166
HHI = .5^{2}+.33^{2}+.16^{2}
HHI =0.388
Consolidation of Units
0-No consolidation to 1-One owner for all properties
Consolidation of Units
Consolidation of Evictions
Consolidation of Evictions
Largest Owners of 10% of Units
All other owners
506
Evictions
3,092
Evictions
/ 16k units
/ 151k units
+49%
+32%
Takeaways
- Difficulty in revealing ownership has shifted from messy data to intentional obscurity
- Using Corporate Data reveals ownership obscurity
- Ownership Obscurity hides new scales of consolidation and responsibility for evictions & property conditions
Thank You
Forrest Hangen
hangen.f@northeastern.edu
@forresthangen@sciences.social
Linking Landlords Hangen - APPAM 2022
By Forrest Hangen
