TO: Ellen Vanderslice, Portland Bureau of Transportation, City of Portland FROM: Derek Dauphin, Toulan School of Urban Studies & Planning, PSU SUBJECT: North Williams and Portland Demographic Analysis, 1990-‐2006/2010 The Mississippi and North Williams areas of Portland are often cited examples of ongoing gentrification. As a process, gentrification is complex and place-‐specific; however a common sequence of events involves an aging urban neighborhood with lower than average property values attracting investment by wealthier outsiders who are typically younger than the original/historic residents. As they move in, property values increase and the original residents move out. In this memo I will use census tract data to compare indicators of gentrification in neighborhoods adjacent to North Williams Avenue with the rest of Portland between 1990 and 20101. North Williams neighborhoods include: Eliot, Boise, Humboldt, and Piedmont2. King and Woodlawn neighborhoods were also included due to their proximity to North Williams Avenue (less than 3 blocks). While literature on gentrification lists many telltale signs of gentrification, I have focused on three indicators based on known characteristics of the North Williams area: (1) Changes in the percentage of white and black residents, (2) median household income3, and (3) age. Based on these indicators, I will attempt to answer the following research questions: 1. Do changes in the percentage of black and white residents in North Williams match those of the rest of Portland? 2. Has there been a significant change in median income within North Williams that differs from the rest of Portland? If so, when does this occur? 3. Does the mean age of those living in North Williams neighborhoods differ from that of the rest of the city and has this changed over the last 20 years? These questions are important in understanding the level and timing of change in these neighborhoods. There is a common perception that the most rapid period of gentrification on North Williams occurred since 2000. By starting with data from the 1990 census we can understand what changes were occurring in the prior decade. The 2006-‐2010 American Community Survey (ACS) combines data from across four years to provide us an understanding of the current situation in Portland and North Williams. (Note: Due to the aggregation involved, data is referred to as 2006/2010 in the tables and figures that follow.) Compared to Portland, North Williams has a much larger black4 population (19.6% of all residents compared to 4.5%), median household income across North Williams tracts is slightly higher than Portland’s ($49,510 compared to $48,644), and North Williams’s population is only slightly younger
1 Only tracts within Multnomah County were analyzed. 2 Tracts within theses neighborhoods were selected from a list of 2000 census tracts for each neighborhood
provided by Arlie Adkins (PSU). There were no changes in tract boundaries for North Williams Neighborhoods between 1990 and 2000, for the 2006/2010 ACS survey 2000 tracts 23.01 and 22.01 became 22.03, tracts 23.02 and 22.02 became 23.03, 44 became 9800, 53 and 54 became 106, 64.01 became 64.03 and 64.04, and 301 became 301.01 and 301.02. Changes are from the Population Research Center’s 2000/2010 comparison. 3 Mean age and associated standard deviation (SD) were calculated from categorical data using methods outlined in Rea and Parker (2005). Briefly, the frequency of each age category was multiplied by its mid-‐point (e.g., 12 for the category “10-‐14 years” was multiplied by the 2482 people in this category) to get total years which was 2 divided by the total population in question. SD was calculated: √(Sum of (frequency*(midpoint – mean) ))/n. 4 Changes between the 1990 and 2000 census resulted in confusion around the Hispanic/Non-‐Hispanic question, however these have been overcome by focusing only on those reporting to be white or black.
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(mean age of 36.5 years compared to 37.5 years). To answer our research questions, we must understand how have these indicators changed since 1990. Between 1990, 2000, and 2006/2010 the mean age of residents in each community changed very little – increasing by approximately one year for Portland and North Williams (Table 1). Closer examination of the census data shows that there is a slight aging of the population between 1990 and 2000 with both Portland and North Williams showing only around 9% in the “45-‐54 Years” category in 1990 and about 14% in 2000. Given that all four ranges between 18 and 54 years have 10% or more of the tracts’ population, it is not surprising that the standard deviation for this data is high: Plus or minus 21 years. Changes in median household income and racial composition were more dramatic. Between 1990 and 2010, Portland saw a very small increase in the percentage of black residents, from 3.6% in 1990 to 4.5% in 2010 (Figure 1). At the same time, the black population decreased dramatically in North Williams, from 36.6% in 1990 to 27.8% in 2000 (-‐24.1%). In 2010 it dropped to 19.6%, a 29.4% decrease from 2000 and 46.5% decrease from 1990. The white population of Portland was 87.1% in 1990 and 2006/2010 with an unexplained dip in 2000 down to 78.5%. It is possible this dip is the result of unaccounted for changes in census methodology. In North Williams, the white population has increased as the black population has decreased, rising 15.6% between 1990 and 2010. This is consistent with gentrification. Although the process appears roughly linear over the last 20 years, analysis of median household income data calls this into question. Comparing median household income in North Williams across the last 20 years shows the largest increase occurred during the 1990s, growing approximately 31% from $33,851.00 in 1990 to $44,330.00 in 2000 (Tables 2 & 3). Over the last ten years, the median income increased a further 11.69%, although this lower growth was no doubt influenced by the late-‐2000s recession starting in 2007 or 2008 and therefore impacting 2 or 3 out of 4 years worth of data. Median household incomes were graphed for 1990, 2000, and 2006/2010 from lowest to highest income for all tracts in Portland including North Williams (Figure 2). North Williams tracts show consistent income increases across the 20-‐year period (rightward movement on the graph). It is also possible to see the economic expansion of the 1990s with all tracts’ incomes increasing in 2000 and the contraction of the 2000s with all tract incomes decreasing back to levels similar to 1990 (see also Table 3). The data also allow us to examine tracts for outliers, however no individual tracts appear to deviate unexpectedly from the expected income s-‐curve. To confirm that trends in the data were not being influenced by the upper and lower ends of the spectrum, tracts with incomes that differed from the mean by more than two standard deviations in either direction were excluded and the median and mean recalculated. For 2006/2010 data, the medians differed by $128.00 for North Williams and $686.00 for Portland. As one would expect, change in means was greater: $2,001.56 and $3,456.46 for North Williams and Portland. These differences are consistent across years and do not alter the overall trends. The medians and means for Portland and North Williams tract groups were compared and appear to differ, albeit only to a small extent (Table 3). This indicates the data may not fit a normal distribution. A histogram was completed for 2006/2010 data using Excel’s statistical analysis package. This showed positive kurtosis for both North Williams and Portland income datasets (data not shown). Overall, the data are consistent with gentrification, and show that the majority of this occurred during the economic expansion of the 1990s. With more money, it is not surprising that speculative buying in areas like North Williams would increase and then taper off during the late-‐2000s recession, by which time a large portion of North Williams’ black population were already gone.
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Table 1: Mean Age (in Years) of Residents living in Portland and North Williams Neighborhoods, 1990-‐2006/2010
Portland
North Williams
Year
Mean
SD
n
Mean
SD
n
1990
36.6
22.4
118
34.2
22.6
16
2000
36.7
21.5
120
34.6
20.9
16
2006/2010
37.5
21.3
119
36.5
19.7
17
Source: Census 2000, ACS 2006 to 2010 (5-‐Year Estimates) (SE), ACS 2006 -‐-‐ 2010 (5-‐Year Estimates), Social Explorer; U.S. Census Bureau and Social Explorer. Notes: Portland and North Williams are exclusive; tracts were not double-‐counted. Means and SD are estimated from categorical data (see text for methodology). Tract numbers sampled vary due to removal of empty tracts between 1990 and 2000 and changing tract boundaries between 2000 and 2006/2010.
Table 2: Median Household Income (in 2010 Inflation Adjusted Dollars), 1990-‐2006/2010
Portland
North Williams
Year
Median
Mean
SD
n
Median
Mean
SD
n
1990
45,654.00
50,188.15
19,591.97
118
33,851.00
30,239.75
10,055.78
16
2000
53,004.00
58,526.41
22,183.67
120
44,330.00
39,568.31
11,008.41
16
2006/2010
48,644.00
56,744.24
24,174.86
119
49,510.00
45,467.94
11,733.42
17
% Change
6.5
13.1
23.4
N/A
46.3
50.4
16.7
N/A
Source: Census 2000, ACS 2006 to 2010 (5-‐Year Estimates) (SE), ACS 2006 -‐-‐ 2010 (5-‐Year Estimates), Social Explorer; U.S. Census Bureau and Social Explorer. Notes: Portland and North Williams are exclusive; tracts were not double-‐counted.
Table 3: Percent Increase in Median Household Income (in 2010 Inflation Adjusted Dollars), 1990-‐2006/2010 Decade
Portland
North Williams
Median
Mean
Median
Mean
1990-‐2000
16.1
16.6
31.0
31.0
2000-‐2006/2010
-‐8.2
-‐3.1
11.7
15.0
Source: Census 2000, ACS 2006 to 2010 (5-‐Year Estimates) (SE), ACS 2006 -‐-‐ 2010 (5-‐Year Estimates), Social Explorer; U.S. Census Bureau and Social Explorer. Notes: Portland and North Williams are exclusive; tracts were not double-‐counted.
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Figure 1: Percent White or Black in Portland and North Williams Neighborhoods, 1990-‐ 2006/2010
Source: Census 2000, ACS 2006 to 2010 (5-‐Year Estimates) (SE), ACS 2006 -‐-‐ 2010 (5-‐Year Estimates), Social Explorer; U.S. Census Bureau and Social Explorer. Notes: Percentages are of total population including non-‐black/white groups not shown. Portland and North Williams are exclusive; tracts were not double-‐counted.
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Figure 2: Median Household Income by Tract (in 2010 Inflation Adjusted Dollars), 1990-‐ 2006/2010
1990
Median Household Income
$140,000 $120,000 $100,000 North Williams
$80,000
Portland
$60,000 $40,000 $20,000 $0
2000
Median Household Income
$140,000 $120,000 $100,000 North Williams
$80,000
Portland
$60,000 $40,000 $20,000 $0
2006/2010
Median Household Income
$140,000 $120,000 $100,000 North Williams
$80,000
Portland
$60,000 $40,000 $20,000 $0
Census Tracts Ordered by Income
Source: Census 2000, ACS 2006 to 2010 (5-‐Year Estimates) (SE), ACS 2006 -‐-‐ 2010 (5-‐Year Estimates), Social Explorer; U.S. Census Bureau and Social Explorer.
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