The combination of three components: fertility, mortality, and migration, collectively lead to population change. Fertility and mortality events in recent history, including escalated fertility levels associated with the ‘baby boom cohort’ and spikes in mortality linked to the Spanish Flu of 1918 for example, have produced demonstrative demographic effects.
However, both the unpredictability and ability of migration to produce virtually immediate impacts, often enduring for decades across social, cultural, demographic, and economic landscapes, has long captured the attention of scholars and public policy makers alike.
Over the past several decades here in Oregon, migration has undoubtedly shaped the state socially and culturally, but equally pronounced and perhaps more tangible have been the long-term challenges and prospects linked to the reciprocal relationship between migration and economics.
The Beaver State grew by more than 400,000 people during the first decade of this century, and nearly half of the growth was concentrated in Deschutes, Multnomah and Washington counties.
While roughly two-thirds of the state’s population growth was attributable to net in-migration, much of the migration-related growth occurred during the early 2000s. Due to the migration slow-down accompanying the economic recession that began in late 2007, natural increase accounted for a greater share of Oregon’s population growth.
In addition to Deschutes, Multnomah and Washington counties, other counties with significant net in-migration included Clackamas (Portland metro), Lane (Eugene metro), and Jackson (Medford metro). Counties with net out-migration included, from lowest to highest: Wheeler, Wallowa, Sherman, Baker, Harney, Grant, Morrow and Malheur (Figure 1).
Unemployment rates are a lagging indicator of economic performance, but the relationship between net migration and Oregon’s annual unemployment rate is clear: as the state’s unemployment rate climbs, there is a delayed, but pronounced decline in net migration.
Prior to the economic recession that began in December 2007, net migration in Oregon averaged 28,000 people per year. Indeed, Oregon gained the majority of the decade’s 250,000 net in-migrants during this period. From 2008 through the end of the decade, however, net migration averaged slightly more than 16,000 people annually—half of what it was during the beginning-to-middle part of the decade (Figure 2).
Analyzing net migration and other metrics of migration is important for gauging the relative importance of migration, along with fertility and mortality, as components of population change. However, because counties with larger population (often urban counties) will often send and receive greater volumes of migrants compared with their rural counterparts, it is important to consider a migration statistic that summarizes the relative effect of migration across all counties. While it has some pitfalls, the Net Migration Rate (NMR) (Table 1 and Figure 3) provides such comparability.
While Washington County recorded the highest level of net in-migration (35,852) of any county in Oregon, the net gain of 35,434 migrants in Deschutes County represented the highest relative gain. Because Washington County is more than three times as large as Deschutes County, Washington County’s net gain of migrants translated to 7.2 net in-migrants per 100 residents while Deschutes County recorded a 25.1 net in-migration rate. Put another way, 84% of Deschutes County’s gain in population was the result of net in-migration, compared to 43% in Washington County.
Polk, Curry, and Josephine counties recorded the next highest net in-migration rates at 15.2, 13.0 and 11.7, respectively.
The largest net out-migration rates were in the Eastern Oregon counties of Sherman, Malheur and Morrow. Sherman County, for example, recorded a marginal net loss of 133 migrants. However, Sherman’s total population of fewer than 2,000 residents makes it one of the least-populated counties in Oregon. As such, the net loss of more than 100 persons translated into a pronounced relative loss.
Disaggregating domestic and international migrant flow data from the U.S. Census Bureau uncovers an interesting trend for Oregon and its counties.
According to U.S. Census Bureau estimates, during the 2000s, approximately two-thirds of Oregon’s net migrants were domestic migrants; one-third were international migrants. In terms of numbers, 165,000 people were net domestic migrants, leaving 85,000 net international migrants.
As the state average suggests, the net migration in the majority of Oregon counties was due to domestic migration flows. However, some counties had considerably different migration patterns.
In the Portland metro area, for example, Clackamas County reflected many counties across Oregon where net in-migration flows were due to domestic migration (80 percent). However, Multnomah and Washington counties were fundamentally different from the larger state pattern (Figure 4). In Washington County, half of net in-migration was due to domestic migrants and the other half was due to international migrants. In Multnomah County, 90 percent of the net migration gains were attributable to international migrants.
Other Oregon counties where international migration accounted for more than half of the gains in net migration included Benton, Marion and Wasco counties.
Figure 5 is illustrative of general age-articulated migration patterns across the life-course. Persons in their first five years of life have moderate mobility levels that decline through age 17, only to increase significantly at age 18 with moving to college, entering the military or moving for employment following high school. Mobility levels generally fall precipitously thereafter as people settle into jobs and communities.
Using the U.S. Census Bureau definition, which classifies a migrant as someone who crosses political (county) boundaries, Figure 5 illustrates a rather significant decline in the propensity to migrate, across almost all age cohorts, between 2005 and 2009. As explained in Figure 1, the economic recession and housing crisis helped to curb migration rates significantly across virtually all age cohorts.
American Community Survey (ACS) estimates for 2005-2007, the three-year period prior to the economic recession, and for the ensuing three years show a 3.3 percent (+/- 0.8 percent) decrease in the number of movers over the period. Comparing the two periods, the number of migrants declined for virtually all types of moves, but most pronounced were individuals migrating across state lines.
Figure 6 underscores a critically important point—the economic recession did not impede migration rates uniformly across the population. In fact, the opposite is true for Oregon interstate migrants. While there was a statistically significant (95%) decline in the number of migrants moving across Oregon county lines between the two periods, there was no statistically significant decline in the number of interstate migrants with at least a Bachelor’s degree during the period. In other words, mobility levels for migrants with higher levels of educational attainment seemed to be somewhat insulated from the economic recession compared to their less educated counterparts.
The largest sources of migrants to Oregon were from California and Washington. In 2005, 39.8percent (+/- 7.5 percent) and 14.1 (+/- 3.5 percent) of migrants were from California and Washington, respectively. In 2009, however, a decline in migrants from California (24.9 percent, +/- 4.8 percent) led to a corresponding increase in the percentage of migrants from Washington (20.2 percent, +/- 3.6 percent).
According to 2009 ACS estimates, fewer than half of Oregon’s residents were born in Oregon and approximately 1 out of every 7 Oregonians was born in California.
One of the seminal laws of migration, developed by Ravenstein (1885), is that for every migrant inflow, there is a counterstream. Migrant exchanges are often a result of physical distance—places in close proximity share a greater degree of interaction. Figures 7 and 8 underscore these principles of migration.
Where California and Washington were the two greatest sources of migrants to Oregon, these two states were also the top destinations for residents leaving Oregon. In both 2005 and 2009, approximately 40 percent of out-migrants left Oregon for these two states.
Figure 9 assesses the comparability of migration information from three primary sources: the ACS; the number of driver’s licenses surrendered at Oregon Department of Motor Vehicle offices; and, the number of exemptions listed on Internal Revenue Service tax returns for the period.
As Figure 9 illustrates, generally, the data sources confirm the top five origin states for Oregon in-migrants: California, Washington, Arizona, Idaho and Colorado.
Table 2 reports county-specific net migration figures for the three-county Portland region (Multnomah, Washington, and Clackamas counties). The largest absolute flow of migrants out of the Portland region is to Clark County, WA. According to 2004 IRS tax return data, there were almost 4,000 more out-migrants to Clark County, WA compared to in-migrants to the Portland region. The largest net flows of in-migrants come from Los Angeles County, CA and Lane County, OR at 1,300 and 700, respectively.
Because counties with larger populations often send and receive greater volumes of migrants, migration streams are often analyzed in terms of relative flow by using a measure of Demographic Effectiveness, or how ‘effective’ migration streams are at redistributing population. Relying on this metric, the most effective county-specific out-migration streams are to Clark, WA and Deschutes, OR. Conversely, the most effective county-specific in-migration streams are all from California—Alameda, Los Angles, and Orange counties.
With an increasingly globalized economy dependent on a highly skilled and well-educated workforce, the future may lead to demand for human capital exceeding the state’s supply from institutions of higher learning. If this is the case, Oregon will continue to be dependent on continued importation of human capital through in-migration. What is clear, with history as a guide, is an inextricable link between in and out migration streams and Oregon’s economy—as demography will undoubtedly determine Oregon’s economic destiny.
Sheila Martin, Charles Rynerson, Risa Proehl and Michael Burnham contributed to this report.