This document summarizes a study that mapped same-sex couple concentrations in Portland, Oregon using 2000 and 2010 Census data. The researchers found clusters of same-sex couples in northeast and southeast Portland in 2000 that dispersed somewhat by 2010, with increased presence in north Portland. Median household income increased between 2000-2010, correlated with some dispersal of same-sex couple clusters. Further analysis of neighborhood characteristics and LGBT business patterns over time could provide insights but are limited by Census data constraints.

1. Portland Same Sex Partner
Spatial Analysis
A. Donald and J. Waldo
USP 531
Dr. Shandas
3/16/2015

2. INTRODUCTION
There are very few surveys that obtain data on the spatial location patterns of the Lesbian, Gay,
Bisexual, and Transgender (LGBT) community. This community’s tendency to gravitate toward
diverse metropolitan areas makes accurate random sampling difficult to conduct. The US Census
Bureau has the largest collection of LGBT spatial data through the decennial census.
Unfortunately, the most precise extent of this data is census tract, and it only records same sex
couples. These limitations are problematic on multiple levels. Despite these parameters, Gary
Gates and Jason Ost used data from Census 2000 to map same sex couple concentrations across
the United States in the Gay and Lesbian Atlas. Their research proved gays and lesbians live in
almost every county in the United States.
We intend to replicate their methods in Multnomah County for 2000 and 2010 to answer the
following research questions:
Does the existing census data on same sex unmarried partners yield results when
mapped using GIS? Do gay and lesbian couples cluster within Multnomah County,
and if so have these communities moved overtime? Second, are there any notable
neighborhood characteristics that correlate with same sex couple concentrations,
such as median household income level or age?
To our knowledge, there has not been a follow up study of the Portland Metropolitan area since
the 2010 decennial census. Nor has there been an analysis of same sex couple movement using
census data.
We are hopeful that clusters of same sex couples can be used to indicate neighborhood locations
of the overall LGBT community, despite the limitations of US Census data. If so, this framework

3. could be replicated for other metropolitan areas and used to identify neighborhoods that might
benefit from additional LGBT community services, specifically health and social services. The
LGBT community is more at risk than general population for a wide spectrum of mental and
physical health issues according to the Centers for Disease Control and Prevention (CDC, n.d.).
Economic development for LGBT oriented businesses could also benefit from this study. Studies
like this can contribute to the current knowledge base and add to the general understanding of a
once, and often times still, invisible community.
DATA SUMMARY
Our two main data sources include Metro’s Regional Land Information System (RLIS) and the
United States Census Bureau. US Census Tract Boundaries of the Portland Metro area in 2000
and 2010 were downloaded as shapefiles from RLIS to provide an outline of US Census tracts in
the Metro area. The river fill feature class is from RLIS as well and contains outlines of streams,
rivers, and lakes. This layer was used to demarcate the Willamette and Columbia Rivers. RLIS
Major Arterials feature class provided a regional street map, and included attribute information
like street names.
Many different forms of census data were accessed through American Factfinder. Maps contain
US Census Tract TIGER/Line shapefiles of the Portland metropolitan area from 2000 and 2010.
Attribute information for these files includes county, census tract polygons, tract numbers and
FIPS codes. 2000 and 2010 Decennial Census Summary File 1 data was accessed through
American Factfinder as well. 2000 same sex couple data was compiled from “Data for
Unmarried Partners by Sex of Partners” ( table ID: PCT014). 2010 same sex couple data was
accessed from “Husband-Wife and Unmarried Partner Households by Sex of Partner” (table ID:
PCT15). Multnomah County was the geographic extent for both sets of data and census tract was

4. LGBT%FLOWCHART
Data$Sources Data Methods Output Analysis
%
Couple%
IndexDecennial%
CENSUS%
Data
Median%
Household%
Income
Decade%
%Chloropleth%
Maps
Anselin%
Moran's%I
Age%
Clustering/%
Change%over%time
Neighborhood%
Charact.
Gentrification
CENSUS%
Long%Form%1990%
&%
ACS%2010
Attribute%%
Chloropleth%
Maps%&%Graduated%%
Symbols
SS%Couple%
by%Tract
Regional%%Land%
Information%
System
Portland%Metro%
Shapefiles

5. the degree. Both tables included census tract numbers, FIPS locators, total house-holds, male-
female unmarried partner households, male-male unmarried partner households, etc by each
census tract for Multnomah County. Median household income was downloaded from American
Factfinder for Multnomah County by census tract from the 2000 Census Longform and the 2010
American Community Survey (5 year estimates). Data tables included the FIPS locator, census
tract numbers, total households and median household income for each census tract. Median
household age was downloaded from census summary file 1 for 2000 and 2010. Data tables
included the median age for males, females, and the total population for each census tract in
Multnomah County.
METHODOLOGY
The base map for every figure consists of RLIS major arterials, river fill, and census tract
outlines for the Portland Metropolitan Region. Separate data was downloaded and compiled for
2000 and 2010 to ensure tract boundaries remained consistent with the table information by
decade. Each map also contains a Census 2000 and 2010 TIGER/Shapefile of census tracts
clipped to Multnomah County.
We used Excel to process same sex unmarried partner data tables for 2000 and 2010. Male and
female same sex couples were summed to create a new field of total same sex couples. Total
households were summed for four different fields: male couples, female couples, same sex
couples, and all households in the county. These data were then normalized using an index
replicated from Gates and Ost for total same sex couples, and male and female couples:

6. Tables were joined to the Census 2000 and Census 2010 TIGER/Shapefiles using the FIPS tract
identifier codes for Multnomah County. Symbology consists of chloropleth maps using the
“index” field as the value. Labels were classified manually into four categories. The lowest
displays a range of zero to one, while the three higher levels represent three relatively equal
intervals. For example, the index field for male couples in 2000 consists of these four levels: 0-1,
1.01-1.78, 1.79-2.56, and 2.57-3.33. The index measures concentration instead of total
populations. In this study, an index of 1 means a same sex couple is just as likely as any other
household to reside in the census tract, and an index of 2 means they are twice as likely. This
was done to produce a different map for each index creating a total of six maps: total index, mm
index, and ff index for 2000 and 2010 (Figures 1-3). Maps are grouped by index, so each page
displays 2000 and 2010.
We then ran Anselin Local Moran’s I, a cluster outlier analysis tool, to identify spatial clusters of
census tracts with similar magnitudes of index measures. To do this, the tool calculates the p-
value of all the competed Moran’s I values as well as assigning code representations for the
cluster and outlier types (COType). The (CO-Type) are statistically distinguished by a
significance level of < 0.05 and are clustered in to four distinct fields: high-high clusters: high
index values surrounded by other high index values (HH); low-low clusters: low index values
surrounded by other low index values (LL); high-low outliers: high values surrounded by low
values (HL); and low-high outliers: low values surrounded by high values (LH). This produced
six more maps (Figures 3-6).

7. Median household income and age were joined using FIPS locators to Census 2000 and 2010
maps. These fields were symbolized as chloropleth maps and classified into five quantiles. Total
same sex couple populations were overlaid using graduated symbols (Figures 7-8).
ANALYSIS
Same sex couple clusters are visible within Multnomah County. The 2000 index for total same
sex couple concentrations shows clusters with indices between 2.55 and 3.30 centered around
NE Fremont and 15th Ave. (Figure 1). Census tract 28.0 also has a high index, located near the
intersection of Sandy Blvd. and 62nd Ave. This means same sex unmarried partners are
anywhere from 2.6 to 3.3 times as likely as all other households to reside in these tracts. By 2010,
only two tracts with a fourth level index remain. Clustering is still visible in Portland, but not at
the same concentration levels. One of the remaining tracts is south of the NE Fremont and 15th
Ave intersection. The other 2010 high concentration tract is census 35.02, bounded by Greeley,
Mississippi, and Going Streets. In 2000, it had an index of 1.5 and in 2010 concentrations
increased to 2.2. There is also an increased index in North Portland in the St. John’s area.
Notably, the total same sex couple concentration levels are lower in 2010, compared to 2000
according to the index.
Female couples appear to follow the same trends as the total same sex couples index (Figure 2).
In 2000, tracts with high indices are predominate in the NE and SE quadrants. By 2010, it
appears there is less concentration in the SE and increased presence is visible in the North.
Between 2000 and 2010, the minimal concentration downtown seems to have disappeared. Index
levels for female couples have decreased over the past decade, suggesting a dispersion of

8. clustering. Granted, the female index was much higher than the male and total couples index in
2000.
In some areas male couples appear to follow a similar path to their female counterparts. In 2000
male couples seem to concentrate sporadically, with a high index in North Portland and another
at the same intersection of NE Fremont and 15th Ave. There are also concentrations in the far
southeast and west sides. By 2010, male concentrations seem to have moved inward. There is a
notably higher concentration in census tracts 56 and 57 where indices increased from 0.7 and 1.4
to 1.8 and 2.4 respectively. There is a pretty clear dispersal of the male cluster in the central NE
quadrant between 2000 and 2010. Concentration levels of the male index have remained the
same between 2000 and 2010.
Median household income and the quantity of same sex couples have increased between 2000
and 2010. There is an evident increase in median household income in the NE quadrant in the
shape of a cross. This area is on the edge of the cluster at the intersection of NE Fremont and
15th Ave. North Portland has consistently low median income levels between 2000 and 2010.
Median age levels have remained relatively consistent and there are no visibly notable changes
between 2000 and 2010. The increase in total population of same sex couples is evident through
the graduated symbols in these maps. It appears same sex couple populations have increased in
almost every census tract.

9. CONCLUSION
We successfully mapped same sex unmarried partner census data using GIS and the outputs yield
visible results. Statistically significant clusters are clearly discernible in both 2000 and 2010.
Male couples and female couples share some spatial location patterns and diverge in other parts
of the city. Movement of the clusters is evident between 2000 and 2010. Clusters of both occur
in NE and SE Portland in 2000. There was a predominately female couple movement from SE
and NE to North Portland over the last decade. Though male couples followed this trend, there
was also significant movement to the central business district between 2000 and 2010. Median
household income levels have increased between 2000 and 2010. There appears to be a slight
correlation between the dispersal movement of same sex couples, and increases in median
household income in NE Portland, but more research needs to be conducted. Maps of median age
do not yield any discernible results.
FURTHER RESEARCH
The most dire research question we have is whether or not unmarried couple census data is
indicative of areas where the broader Lesbian, Gay, Bisexual, and Transgender community
resides. If so, mapping same sex couples could be an inexpensive way to analyze the potential
LGBT neighborhoods across the nation. We would use a survey to certify these neighborhoods
and most likely poll businesses, houses, and LGBT people in the area.
Analysis of the increase in same sex couples between 2000 and 2010 needs to be conducted. This
could be done by looking at the total household population increases and comparing them to
same sex couple population increases. Census tracts should be broken down one by one to look
for significant results.

10. We would like to compare more neighborhood characteristics with LGBT clusters. These can
include, but are not limited to, educational attainment, property values, and ethnicity. Other
measures of neighborhood amenities could aid in analysis for gentrification.
While we were able to begin to collect the relevant data of LGBT businesses in Portland, time
became a constraining issue for this analysis. We discussed weighting establishments differently
and then adding them to the index. For example, LGBT organizations might be a 5, bars and
restaurants a 3 and LGBT owned businesses a 1. Further data, methodology, and projected
analysis are outlined in detail in the LGBT Business Appendix.
LIMITATIONS
A small population size is generated from the 2000 and 2010 census and census tracts are large
areas to measure small populations with. Same sex couples do not give an accurate portrayal of
the LGBT population.
Due to the limitations of the census, many individuals are missed in this analysis. The population
measured is exclusive to those who have self-identified on the census form as unmarried same
sex partners. This excludes a large sector of the LGBT population as this not only requires the
individuals to cohabitate but also to identify as “unmarried partners” as well as falling into the
same sex category. Additionally, individuals across the transgender spectrum are likely
miscounted as the census would consider these individuals as heterosexual partners.
Heterosexual individuals mistakenly selecting the option of “unmarried partner” may make for
additional error. It can be said Census Data for unmarried same sex partners is not the most

11. We also regret using all of Multnomah County. Results may have been more accurate if large
tracts with very low total household populations, but high same sex couple populations were
removed from the study area.
-BUSINESS APPENDIX-
DATA
LGBT serving businesses were identified using four major directories (Gay Yellow Pages;
Travel Portland, LGBT; Gay Cities; and Gay Yelp) as well as a general google search to
determine if any businesses were excluded from the directories. A historical database compiled
by Gay & Lesbian Archives of the Pacific Northwest (GLAPN) was utilized as a supplemental
resource. Additional google searches were done on each business to determine open and close
dates, however due to the lack of this information, business data was ultimately excluded from
the final analysis.
METHODOLOGY
Self-identified LGBT businesses were entered into an Excel spreadsheet and then geocoded to
the Multnomah County tracts for Census 2000 and 2010. The addresses were geocoded based on
what was given in the directories and no verification process was applied.
POTENTIAL IMPLICATIONS
Future studies can map the movement of LGBT businesses to examine the potential effects of
gentrification. The historic downtown triangle is still visible in 2010 (Figure). Tentatively our
research shows that eight businesses have left this downtown area since 2000. Between 2000 and

12. 1990 we believe the number is even higher. We would like to compare this data with median
household income levels and property taxes to see if business movement correlates to increasing
income levels.
This study would require a qualitative component in the form of a survey and individual
interviews. Questions would be used to ascertain approximate open and closing dates of venues
and other underground LGBT establishments that may not be listed in the directories. A
qualitative study could also garner more information as to the reasons why these businesses shut
down.

13. Total Same Sex Couple Index 2010 Portland, OR
Total Same Sex Couple Index 2000 Portland, OR
Legend
Index
SS Couple Total
0.07 - 1.00
1.01 - 1.77
1.78 - 2.54
2.55 - 3.30
Legend
Index
SS Couple Total
0.15 - 1
1.01 - 1.63
1.64 - 2.26
2.27 - 2.9
0 2.5 5 7.5 101.25
Miles
0 2.5 5 7.5 101.25
Miles
FIGURE 1

14. Female Same Sex Couple Index 2010 Portland, OR
Female Same Sex Couple Index 2000 Portland, OR
0 2.5 5 7.5 101.25
Miles
0 2.5 5 7.5 101.25
Miles
Legend
Index
Female Couples
0.00 - 1.00
1.01 - 2.01
2.02 - 3.04
3.05 - 4.04
Legend
Index
Female Couples
0.12 - 1.00
1.01 - 1.75
1.76 - 2.50
2.51 - 3.24
FIGURE 2

15. Male Same Sex Couple Index 2010 Portland, OR
Male Same Sex Couple Index 2000 Portland, OR
0 2.5 5 7.5 101.25
Miles
0 2.5 5 7.5 101.25
Miles
Legend
Index
Male Couples
0.00 - 1.00
1.01 - 1.78
1.79 - 2.56
2.57 - 3.33
Legend
Index
Male Couples
0.05 - 1.00
1.01 - 1.74
1.75 - 2.48
2.49 - 3.23
FIGURE 3

16. Total Same Sex Couple Clusters 2010 Portland, OR
Total Same Sex Couple Clusters 2000 Portland, OR
0 2.5 5 7.5 101.25
Miles
0 2.5 5 7.5 101.25
Miles
Legend
Not Significant
High-High Cluster
High-Low Outlier
Low-High Outlier
Low-Low Cluster
No Data
Legend
Not Significant
High-High Cluster
High-Low Outlier
Low-High Outlier
Low-Low Cluster
No Data
FIGURE 4

17. Female Same Sex Couple Clusters 2010 Portland, OR
Female Same Sex Couple Clusters 2000 Portland, OR
0 2.5 5 7.5 101.25
Miles
0 2.5 5 7.5 101.25
Miles
Legend
Not Significant
High-High Cluster
High-Low Outlier
Low-High Outlier
Low-Low Cluster
No Data
Legend
Not Significant
High-High Cluster
High-Low Outlier
Low-High Outlier
Low-Low Cluster
No Data
FIGURE 5

18. Male Same Sex Couple Clusters 2010 Portland, OR
Male Same Sex Couple Clusters 2000 Portland, OR
0 2.5 5 7.5 101.25
Miles
0 2.5 5 7.5 101.25
Miles
Legend
Not Significant
High-High Cluster
High-Low Outlier
Low-High Outlier
Low-Low Cluster
No Data
Legend
Not Significant
High-High Cluster
High-Low Outlier
Low-High Outlier
Low-Low Cluster
No Data
FIGURE 6

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Median Household Age and Same Sex Couples 2000
Median Household Age and Same Sex Couples 2010
0 2 4 6 81
Miles
0 2 4 6 81
Miles
Legend
0 - 18
19 - 37
38 - 55
56 - 74
75 - 92
22 - 33
34 - 35
36 - 37
38 - 41
42 - 54
Age
Total SS couples
Legend
Total SS couples
!(
1 - 14
!( 15 - 26
!( 27 - 39
!( 40 - 51
!( 52 - 64
Age
26 - 32
33 - 34
35 - 36
37 - 39
40 - 49

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Median Household Income and Same Sex Couples 2010
0 2 4 6 81
Miles
0 2 4 6 81
Miles
0 - 18
19 - 37
38 - 55
56 - 74
75 - 92
13283 - 38695
38696 - 45779
45780 - 52949
52950 - 67431
67432 - 141543
Legend
Total SS couples
!(
1 - 14
!( 15 - 26
!( 27 - 39
!( 40 - 51
!( 52 - 64
Median HH Income
8179 - 29730
29731 - 41361
41362 - 53047
53048 - 71321
71322 - 111064
Legend
Total SS couples
Median HH Income
Median Household Income and Same Sex Couples 2000