America鈥檚 homeless services system relies on a massive amount of data, and at first glance, that data is exacting. Federal reports describe the country鈥檚 unhoused population in granular detail, listing precisely how many people are experiencing homelessness in each city along with detailed demographic data. Want to know how many people ages 55-64 slept outside in Spokane last year? A spreadsheet confidently provides the answer: 听

That data influences decisions at every level of government, from how the U.S. Department of Housing and Urban Development (HUD) distributes $3 billion in funding to how local service providers target their outreach efforts. It鈥檚 also . As a result, communities across the country 鈥� including King County 鈥� don’t really know exactly how many of their residents are unhoused and have a limited window into people鈥檚 circumstances and needs. 听

So, a team of 91探花 researchers designed a better way to count. Led by , a 91探花associate professor of sociology, and , professor emeritus of health systems and population health, researchers developed a method that taps into people鈥檚 social networks to generate a more representative sample, which they use to estimate the total unhoused population. Along the way, agency staff and volunteers gather information on people鈥檚 demographics, resources and needs. 听

The researchers launched this method in partnership with King County in 2022 and repeated the process in 2024, publishing their findings . 91探花News sat down with Almquist and Hagopian to discuss their new approach and how it could help close the gaps in our understanding of homelessness in America.听

Statistics on homelessness and the demographics of unhoused populations are often quite specific. The federal government reported that on a single night in January 2023, for example. How do we get these statistics, and how reliable are they?听听

Amy Hagopian: I鈥檓 always a little amused at numbers that create a false specificity; for example, an airline says my flight will arrive in Chicago at 11:33 a.m. Everyone knows that number isn鈥檛 true, except sometimes by accident, and yet we entertain the airline by pretending to believe the number. After all, there are no consequences for being wrong!听

The national count is an amalgamation of counts reported by each community鈥檚 jurisdiction, designed by the U.S. Department of Housing and Urban Development. Most jurisdictions are still attempting a single-night head count of people found by volunteers who move about in the dark with flashlights and clipboards 鈥� a highly problematic approach King County has abandoned in favor of our sampling method. When these numbers come in, HUD just adds them up, and of course the number won鈥檛 be round. We all know it鈥檚 way below the actual number, because a middle-of-the-night census isn鈥檛 going to find everyone.听

Zack Almquist: There is a common fiction that when we do a census it is exact, because government reports often do not provide a margin of error. I think if you asked many experts, they would say they know the reality is a range, not a single number. In fact, not providing a range provides a level of confidence that we really don鈥檛 have, regardless of how we get there.

One nice thing about using a statistical estimate is that people are trained to expect a margin of error or confidence interval. We can say, plus or minus 5%, or 100-200 people. In other words, by moving into a space where we expect to see a range, we can be more honest, and ideally be more prepared to handle the real situation.听

Why does it matter how accurate this data is?听

AH: America has the worst homelessness problem in the world created by an economic system 鈥� as opposed to war and other disasters 鈥� largely because we make no attempt to recognize the human right to housing as established by the United Nations. One reason to count by jurisdiction is to learn where the hot spots are, and which areas have managed to lower their counts, and why. 听

ZA: This is also an equity and respect issue for the people who are experiencing homelessness. We owe it to our community members to do our best to capture the real state of the problem in our area and to best represent their race, ethnicity, gender, disability status, and causal or associated factors like eviction. We cannot hope to adequately engage a problem if we can鈥檛 accurately quantify it.

Your team developed a new method to estimate the unhoused population. How does your method work, and how does it differ from the traditional PIT count?听听

ZA: Our method takes the approach that there is no reliable way for us to obtain a census of people living unsheltered in our community, and that we need to move from a biased counting exercise to an approach that leverages modern statistical methods to obtain a best estimate of the population given our current resources. Modern sampling methods can improve how we count people. Sampling is the process of selecting a small group from a larger population to study and make conclusions about the entire population.听

We leveraged a sampling strategy that comes out of public health literature and is endorsed by the National Institutes of Health and World Health Organization. First, we collect a roster and bed count from shelters. The HUD-mandated Point-in-Time count was always split between the roster or bed count and an unsheltered count; the latter was historically counted in King County by a visual census. So, the total number of people experiencing homelessness is the number of people in emergency shelters on a given night plus the number of people living outside on a given night. Through some ratios and algebra, we can estimate the total number of people if we know who slept in an emergency shelter and know from historical measures the relative proportion of people who slept outside. 听

Our sampling strategy of leveraging people鈥檚 social networks and peer referral allows us to estimate the proportion of people who slept outside to those who slept in an emergency shelter on a given night. Further, this allows us to better find and count people who would be hard to find in the traditional visual census 鈥� people living in the woods or hiding 鈥� and also provides a clear method for the margin of error of our estimate of the number of people experiencing unsheltered homelessness.听

Your count creates a more reliable estimate of the unhoused population, but that鈥檚 not all. What other information can you collect with this method, and how might it be useful?听听

AH: When other jurisdictions do their midnight census counts, they are just counting bodies seen. There is no opportunity to collect demographic or life history or health status data unless they shake people awake and interview them in the moment, which few people do. Instead, they conduct a post-count interview process in places like food banks. Our approach provides the opportunity to count people during daylight hours while also learning something about their life course and circumstances. This provides King County with some valuable information about the causes of homelessness. Once we move towards a quarterly count, we can also learn about the 鈥渃hurn鈥� —听the number of people moving into and out of homelessness and what the drivers are for those changes in circumstance.听

ZA: I think this point can鈥檛 be emphasized enough, as running a post-count survey is almost always conducted as a spatial convenience sample that surveys both those using emergency shelters and those who slept outside. It鈥檚 unlikely to include the same people who were in the one-night body count. 听

What have you heard from people who鈥檝e participated in your method? How do participants鈥� experiences differ from the old Point-In-Time count?听

AH: We conducted a couple of focus groups recently with people experiencing homelessness in Seattle. We asked them about their impressions of the recent methods change in how we count. We found people appreciated the motivations behind the change, and the more respectful approach we are now using.听听

ZA: I just want to second what Amy said, and to point out that people really appreciate being directly engaged with and having a chance to be paid for their time and effort.听

How else could this method be used? Are there potential applications outside of homelessness and housing services?听听

AH: I have helped conduct mortality counts in war zones, and some of the lessons learned from those experiences were helpful here. For example, in Iraq conducted a door-to-door survey to ask adult household members to tell us about the alive or dead status of their siblings. This allowed us to calculate a total war-related mortality rate for the country, as our sample was selected proportionate to size of the governorate sampled. 听

ZA: I think the basic ideas used here could end up influencing health and demography measurement efforts for several hard-to-estimate populations. For example, international migration can often be split between those we can count with high fidelity, like registered immigrants, and unregistered immigrants. Combining new sampling methods with administrative data to count hard-to-reach populations could be employed for a number of problems in industry, health and public policy. I hope to see these ideas picked up broadly.听

AH: We are grateful to the UW鈥檚 Population Health Initiative for the opportunity to develop these methods, and to our partners at King County Regional Homelessness Authority for being willing to try something new with us.听

For more information or to contact Hagopian and/or Almquist, contact Alden Woods at acwoods@uw.edu.听听

When 91探花 President Ana Mari Cauce launched the Population Health Initiative in 2016, she spoke in soaring, ambitious terms. 鈥淲e have an unprecedented opportunity to help people live longer, healthier, more productive lives 鈥� here and around the world,鈥� she said. 91探花researchers have leapt at that opportunity, forging connections across the university, working side by side with community partners and breaking down traditional barriers to improving public health. 听

In just eight years, the Initiative has funded 227 innovative, interdisciplinary projects. Many are focused right here in Western Washington, where projects have helped in South Seattle, identified soil contaminants in community gardens in the Duwamish Valley, and improved how community leaders along the Okanogan River . Other projects have reached across the globe, targeting health disparities in Somalia, Peru, Brazil and more.听听

鈥淚n this relatively short period of time, we鈥檝e demonstrated the power that accrues when faculty and staff across the various areas of our campuses are working together and also exposing students to the cutting-edge work of tackling grand challenges,鈥� Cauce said in her most recent .听

And they’re just getting started. Many PHI-funded projects are still in their earliest stages, leveraging initial funding to show proof-of-concept for their ideas and setting the stage for future work. Fourteen projects so far have received much larger grants to empower researchers and community partners to expand successful projects and scale up for greater impact.听

With the Initiative now a third of the way into its 25-year vision, 91探花News checked in with three projects that recently received funding to scale their efforts.听

Spotting potential memory health issues in rural Washington

Diagnosing memory health issues in the best of circumstances is extraordinarily difficult. Patients typically make multiple visits to their doctor and take a many of which can produce flawed results 鈥� people who take the same test more than once, for example, will often score higher, potentially masking memory loss. 听

It鈥檚 even harder in rural America, which has a Patients seeking memory care might have to make a long, expensive trip to a major city, which leads many people to wait until a problem becomes apparent. By then, it鈥檚 often too late 鈥� modern treatments can slow the progress of memory loss, but there鈥檚 no way to regain what鈥檚 been lost.听

鈥淪o, how do you catch it early?鈥� said , a 91探花associate professor of psychology. 鈥淲e give people an app to have them check for themselves.鈥澨�听

Stocco and , director of the 91探花Alzheimer鈥檚 Disease Research Center, together with Hedderik van Rijn of the University of Groningen in the Netherlands, led the development of an online program that can measure a person鈥檚 memory and predict their risk of memory disorders. Like a flash-card app that helps students cram for a test, the program shows pictures and asks the user to recall what they saw a few minutes earlier. The app records how quickly and accurately the user responds to each question and makes the next one a little easier or more difficult.听听

Researchers have long understood that a person鈥檚 ability to recall a specific memory tends to fade over time. This is called the 鈥�.鈥� In听 Stocco and van Rijn found that they could measure individual differences in the slopes of such curves.听 The app works by comparing a person鈥檚 responses to an internal model of forgetting and adjusting the slope of the model until it matches the responses. The resulting slope can be used to estimate the likelihood that their memory is fading faster than normal.听听

By taking the test regularly, a person can track their memory鈥檚 decline over time. But preliminary tests, Stocco said, have shown that even a single use can spot a potential problem.听

鈥淛ust by looking at a single lesson, based on the result, there鈥檚 almost a perfect correspondence between the speed of forgetting and your probability of being diagnosed by a doctor,鈥� Stocco said. 鈥淚t can be as accurate as the best clinical tests but, instead of taking two or three hours, this can be done in eight minutes, and you don鈥檛 need a doctor.鈥�听

A Tier 3 grant from the Population Health Initiative and a collaboration with the will allow the researchers to share the app with up to 500 people in rural and counties. Participants can take the test on their own time, and the results will be shared with researchers. If a potential problem emerges, the researchers plan to invite participants to Seattle for an in-person evaluation.听听

鈥淚t鈥檚 a solution that seems to solve these problems of early access and diagnostic bottlenecks,鈥� Stocco said. 鈥淚f this works, there鈥檚 no problem giving it to everybody in the state. We鈥檙e really interested in expanding and adding people from underrepresented populations and underrepresented areas, and the grant will allow us to do that.鈥�听

Nancy Spurgeon of the Central Washington Area Health Education Center is also a collaborator on the project to test the prototype app, which is not yet available to the public.听

Revamping the Point-In-Time Count to better understand King County鈥檚 unhoused population听

For years, volunteers fanned across King County on a cold night each January, flashlights and clipboards in hand, searching for people sleeping outside. They鈥檇 also gather the shelter head counts for that night. Officially called the , this effort attempted to tally the number of people who lacked stable housing. This endeavor was replicated in cities across the country, and the results were combined to create a national count that influences how the federal government allocates funding.听

There鈥檚 just one problem 鈥� the count is Volunteers can鈥檛 possibly find everybody. It captures only a single moment in time, and collects only limited data on people鈥檚 circumstances or personal needs. A person sleeping in their car might need different services than a person who sleeps in a tent, and the count didn鈥檛 fully capture that distinction.听

So, a team of 91探花researchers designed a better way to count. Their method, detailed in a published Sept. 4 in in the American Journal of Epidemiology, taps into people鈥檚 social networks to generate a more representative sample, which the researchers then ran through a series of calculations to estimate the total unhoused population.听听听

Called 鈥渞espondent-driven sampling,鈥� the method stations volunteers in common 鈥渉ubs,鈥� like libraries or community centers, and offers cash gift cards for in-person interviews and peer referrals. Volunteers collect detailed information on people鈥檚 circumstances and needs, giving each person three tickets to share with their unhoused peers. When those peers come in for an interview and show the ticket, the person who referred them receives another small reward. The new person gets a gift card and another three tickets.听

鈥淭his method gives people a more active voice in being counted. It鈥檚 a more humane way to count people, and it鈥檚 also voluntary,鈥� said , a 91探花associate professor of sociology and co-lead on the project. 鈥淭he regular PIT (Point-In-Time) count just counted people. Now we can collect all sorts of information from people on their circumstances and their needs. Should policymakers want to, they could leverage that data to change service offerings.鈥�听

The researchers received a Tier 2 grant to develop the system. They launched it in partnership with King County in 2022 and 2024, and were recently awarded a Tier 3 grant to test out the feasibility of running it quarterly.听听

鈥淩unning the count quarterly allows us to estimate how many people move in and out of homelessness and whether there are seasonal changes, which are rarely measured,鈥� Almquist said. 鈥淎lso, people鈥檚 needs change depending on the time of year, and this method will help us better understand those rhythms.鈥澨�听

Other cities and counties have expressed interest, the researchers said. The team has also begun to expand the effort, aiming to improve data across the broad spectrum of housing and homelessness services.听听

鈥淎 very important byproduct of this work across schools and departments at 91探花is that we can create an ecosystem of people and projects,鈥� said , a 91探花professor emeritus of health systems and population health and co-lead on the project. 鈥淲e鈥檝e spun off projects on sleep assessments, relationships with organizations that collect data on homelessness, and we鈥檙e mapping the sweeps of encampments in relationship to where people choose to be located. We have a whole network of homelessness-related research now.听

鈥淭hese PHI grants gave us the fuel to ignite these projects.鈥�听

Other collaborators are of the 91探花Department of Health Systems and Population Health and of the VA Health Services Research and Development; of the 91探花Departments of Sociology and Statistics; of the Center for Studies in Demography & Ecology and the eScience Institute; and Owen Kajfasz, Janelle Rothfolk and Cathea Carey of the King County Regional Homelessness Authority.听

Engaging community to mitigate flood risk in the Duwamish Valley听

More than a century ago, Seattle leaders set out to control and redirect the Duwamish River. They dredged the riverbed and dug out its twists and turns. Wetlands were filled in, the valley was paved over and a system of hydrology was severed. What had been a wild, winding river valley with regular flooding became an angular straightaway built for industry. But when 91探花postdoctoral scholar looks out at the Duwamish, she sees the river fighting back.听听

鈥淭he water was always there,鈥� Jeranko said, 鈥渁nd now it鈥檚 fighting to come back up.鈥澨�听

The river returned with devastating effect in December 2022, when a king tide and heavy rainfall , submerging homes and shuttering local businesses. The underserved neighborhood faces a significant risk of future floods.听

To mitigate that risk, the City of Seattle has updated the neighborhood鈥檚 stormwater drainage system and launched a new flood-warning system. But the , a nonprofit focused on river pollution and environmental health, saw an opportunity for something greater. The DRCC asked a team of 91探花researchers to help develop flood adaptation plans that are community-based, culturally responsive and that enrich the local environment.听听

鈥淚n the community, people don鈥檛 think there鈥檚 been enough engagement. There鈥檚 all this talk about flood mitigation, but all they see are sandbags,鈥� Jeranko said. 鈥淪o DRCC was like, 鈥楲ook, we really need the people who live in the flood zone to understand the solutions.鈥� Because we have this long-lasting relationship with them, they see us as someone who鈥檚 able to provide a list of solutions, not favor one over the others, and do it in an informative way.鈥�听

Boosted by a Tier 3 grant from the PHI, Jeranko and a team representing five 91探花departments, the Burke Museum and the DRCC are engaging with the community. This fall, the team will present the neighborhood with an expansive list of flood mitigation options and encourage city leaders to consider people鈥檚 preferences. Early work shows the community would favor nature-based solutions, Jeranko said. Floodable parks, for example, would provide ecological, recreational and public health benefits to the entire community, while storing flood water during storms.听听

鈥淚t has been wonderful to collaborate with the 91探花team on this to make sure we are centering community voices in every single step of the planning for climate resilience,鈥� said Paulina L贸pez, executive director of the DRCC. 鈥淐ommunity leadership and representation is indispensable to bring climate justice to the Duwamish Valley.鈥�听

Jeranko hopes their community-based model will be replicated by communities across the country facing similar risks from climate change and sea level rise.听

鈥淓ven though 91探花and a lot of other universities really support and invest in community-engaged work, a lot of times it鈥檚 fundamentally hard to make that research happen,鈥� Jeranko said. 鈥淏ut the Population Health Initiative grant was about supporting all those things.鈥�听

Other collaborators on the project are , and of the Department of Environmental & Occupational Health Sciences; of the Department of Landscape Architecture; of the Department of Civil & Environmental Engineering, of the School of Environmental and Forest Sciences; of the Quaternary Research Center and the Burke Museum; and L贸pez and Robin Schwartz of the DRCC.听

For more information on any of the projects mentioned, or to learn more about the 91探花Population Health Initiative, visit the Initiative’s website or contact Alden Woods at acwoods@uw.edu.听听

Even before the pandemic left COVID-19 patients with staggering hospital bills, many people, especially those who are uninsured, were often overwhelmed with medical bills

Research shows that medical debt burdens millions of Americans: Depending on how 鈥渕edical debt鈥� is defined, studies from nonprofits and academic institutions generally show from to of adults carry that burden.

And medical debt and housing instability often go hand in hand. In a new 91探花 study of people experiencing homelessness in King County, unpaid medical bills were their primary source of debt, and that debt extended their period of homelessness by an average of two years.

鈥淪o many people have lost their jobs, and then they lose their health insurance. They may not be able to pay even small medical bills or co-pays and still have rent or mortgage payments. If they get sick with coronavirus, or some other medical condition, this can be the perfect storm that puts people out on the street and increases the time they spend there,鈥� said , who conducted the study for her master鈥檚 thesis from the 91探花School of Public Health.

The was published June 8 in the journal Inquiry: The Journal of Health Care Organization, Provision, and Financing.

Little research has been done linking medical debt and homelessness, Bielenberg pointed out. While her study did not find a direct causal relationship between the two, it did determine that among those experiencing homelessness, the inability to pay off medical bills, even a few hundred dollars, was associated with considerably more time spent unhoused.

Bielenberg and her co-authors worked with two Seattle organizations supporting shelters and encampments for the homeless: and Nickelsville. The team surveyed 60 adult residents about their health and financial situation, including other debts and past periods of homelessness. Two-thirds of participants were white; 15% were Black, and 7% were Native American.

Participants whose medical bills had been sent to collections had experienced homelessness for an average of 22 months longer than those who hadn鈥檛 had such trouble paying bills; Black, Indigenous and people of color who were unable to pay their medical bills reported being homeless a year longer than white participants with the same financial challenge.

鈥淚f Black lives really mattered, we wouldn鈥檛 systematically exclude those folks from good jobs 鈥� and a good job in America is a job with health insurance,鈥� said co-author , a clinical instructor in the 91探花Department of Health Services and an organizer with SHARE and Nickelsville.

In all, more than 80% of participants reported having debt of some kind, such as doctor bills, student loans, credit cards or payday loans. Of those participants, 68% reported medical debt, the majority of which had been sent to collections.

In about one-third of cases, the amount of medical debt was relatively small 鈥� less than $300. That underscores what, for many people, can be a domino effect, Bielenberg said: One lost job, or lack of health insurance, can saddle a person with debts they have to prioritize, if they can pay them at all.

Medical debt is a different kind of debt than, say, outstanding credit card bills or student loan payments, which can be protective against homelessness in the short term, Bielenberg explained. Someone making student loan payments has an education, which can enhance their earning power, while credit cards and payday loans can cover basic necessities, even though they come with high interest rates. Medical debt, by its nature, stems from an illness or injury and may accompany job loss or lack of health coverage.

But what might be perceived as a safety net 鈥� health insurance 鈥� wasn鈥檛 always that, Bielenberg found. Two-thirds of participants were enrolled in Washington鈥檚 Medicaid program, Apple Health, while others received coverage from Medicare, the Indian Health Service or the Veterans Health Administration. Some 16% reported having no insurance coverage.

Insurance doesn鈥檛 always cover everything, Bielenberg said, and even the comfortably insured may lose track of costs that are their responsibility.

The study didn鈥檛 examine or advocate for specific solutions, but Bielenberg suggested further research, with larger and more diverse participant pools, could bolster arguments for policy change or new support programs. 鈥淔ortunately and unfortunately,鈥� Bielenberg said, 鈥渨e are in a time of considerable turmoil. Sometimes these moments are the perfect time to completely rethink our ways of doing things. The U.S. could join the vast majority of countries in the world and simply offer universal health coverage. We spend twice per person on medical care than any other country, so we obviously are doing something wrong.鈥�

Co-authors on the study were , a 91探花professor of global health, and , a clinical assistant professor of health services at the UW.

Bielenberg, who is now a survey methodologist at 23andMe in California, received a stipend from the Northwest Center for Public Health Practice to support her graduate studies.

For more information, contact Bielenberg at jessica.bielenberg@gmail.com.