To better understand the needs of the growing houseless population in their communities, local governments need to know how many unhoused people there are in the first place. For nearly two decades the United States Department of Housing and Urban Development required local jurisdictions to attempt a biennial census of unhoused people on a single night in the last two weeks of January. After counting the number of people using emergency shelters, many counties try to quantify how many people are living outside by conducting a Point-in-Time (PIT) count. The most common method involves volunteers walking around at night and making a tally of those they believe are sleeping outside. 

In 2022, the King County Regional Homelessness Authority (KCRHA) sought to improve this procedure and began a collaboration with the University of Washington, led by Sociology Associate Professor Zack W. Almquist. As the Primary Investigator at the head of the Social, Spatial, and Dynamic Analysis Lab, Dr. Almquist works with his team to develop network based methods that improve the process of enumerating those living unsheltered. His lab piloted new software in 2023 for this procedure and helped run the 2024 PIT count with KCRHA. 

This year, Dr. Almquist’s lab worked closely with the UW Scientific Software Engineering Center (SSEC) to co-develop an app with KCRHA that advances this method of data collection. The app hosts a survey as part of an approach created by the lab known as Respondent-Driven Sampling (RDS). RDS involves people experiencing homelessness spreading the survey through peer referral coupons within their community. By following these social connections, the survey reaches far deeper into unsheltered communities than standard counts, helping to paint a more comprehensive and accurate picture of both the number of people affected and their needs.

The software needed for this type of survey is fairly advanced. It must track connections between people while also protecting privacy and ensuring that no one can be personally identified. At the same time, it should be practical for large non-profits and government agencies that are responsible for counting people living outside of the shelter system. SSEC built a system that supports the verification and generation of referral codes for RDS. It also assists with the collection of surveys from respondents and assists researchers in running experiments and analyzing the resulting data. 

Once deployed, a volunteer can access the app on a mobile device. They can login, complete a survey with a respondent, submit the data, then print and give out QR code referrals. App administrators can oversee volunteer activities, manage user access, and monitor regional survey distribution in real-time. Data is managed by cloud solutions that are HIPAA-compliant and enable further data integration with the Homeless Information Management System.

This app was used in the 2026 King County PIT count which is conducted over two weeks at over twenty physical locations. This year, more than 2,000 surveys from people experiencing homelessness were collected at the end of January 2026. The resulting data will be used to make the official unsheltered PIT count for King County under the guidance of Dr Almquist. We expect the results to be announced over the summer. KCRHA will also use the data in conjunction with his lab to develop a local report with detailed information about the current needs of the unsheltered population in the county.

While sharing his thoughts on SSEC’s impact on the project, Dr. Almquist shared that “it has been a pleasure to see this product in action. It’s really made the user experience exceptionally better than in 2024. The improved UI, login, and integrated process have worked really well. We expect a great improvement in our enumeration data this year! The quality of work your team delivered on this effort is evident, especially given the tight timelines. Thanks to your efforts, we’re also able to use the app for the LA youth homelessness count and are expanding our partnerships with more counties in and out of Washington, including Texas.” Janelle Rothfolk, KCRHA’s Senior Research and Data Director added that “the design was easy to use for volunteers on tablets, phones and laptops, and enabled surveys to be collected accurately and efficiently. I look forward to seeing what else SSEC develops!”