Despite decades of research and growing evidence, homelessness remains stubbornly high. The challenge, Teixeira said, is no longer just understanding the problem but aligning systems and acting on the evidence consistently.
“Tackling homelessness is not rocket science. It’s much, much harder,” said the founder and CEO of the Centre for Homelessness Impact. Progress depends on multiple interventions working together. And meaningful systemic change takes time, even when the path forward is clear.
Teixeira’s starting point was simple: treat homelessness as a problem we can learn our way through.
That idea underpins the “what works” movement she has helped bring into the homelessness sector. Borrowed from health research, this approach focuses on testing interventions, evaluating them rigorously and using evidence to decide what to scale up and what to stop.
Over time, that process has transformed how homelessness is understood, and exposed how many existing responses have relied on assumptions rather than proof.
From good intentions to tested solutions
When Teixeira set up the Centre for Homelessness Impact, the evidence base was thin. Fewer than a dozen studies examined which homelessness interventions were actually effective. Today, there are more than 1,600.
She explained that some widely used approaches were never grounded in strong evidence, and others can do harm. “Scared straight” programs, for example, were designed to deter young people from crime by showing them prison environments. The idea felt intuitive, but researchers found it had the opposite effect: participants were more likely to offend.
Canada, Teixeira said, stands out for the strength of its evidence base, particularly its ability to combine qualitative insight with causal research. That balance has helped push the field forward.
Learning what to scale up
To build up evidence-based solutions, Teixeira recommended a “test and learn” model. It treats policy and programming as an ongoing experiment, with interventions deployed, evaluated and refined in a continuous cycle.
Some findings challenge expectations. Studies on direct cash payments to youth, for instance, have shown that recipients tend to make careful, constructive choices with the money. And that trust itself can be powerful.
Even simple actions matter. In one example, contacting people to let them know about available services increased uptake, despite initial doubts that this would have an impact.
These findings identify where limited resources can have the greatest effect. But over time, evidence has also pointed away from searching for a single breakthrough solution.
From isolated interventions to connected systems
One of the clearest lessons from Teixeira’s talk is that no single intervention can solve homelessness on its own.
Housing is critical, but it doesn’t work in isolation. Outcomes improve when it’s paired with other supports — access to health care, legal assistance, income stability and targeted outreach to meet specific needs.
Drawing on public health approaches, Teixeira said that lasting progress depends on investing across the system. This means preventing homelessness, identifying and supporting people at risk and providing effective responses for those already experiencing homelessness. The greatest impact comes not from choosing among these approaches but from co-ordinating them across organizations, sectors and levels of government.
That co-ordination, she added, is where many systems struggle. “Governments often invest heavily in policy design and front-line services while underinvesting in the infrastructure that connects them: shared goals, data, feedback loops, implementation support and continuous learning,” she said.
A positive example is Houston, where public agencies, service providers, funders and community organizations aligned their work around shared goals and co-ordinated funding, data, service delivery and common measures of success. The result was a more cohesive response with stronger outcomes.
Without that alignment, even well-designed programs risk competing with or duplicating one another. Beyond simply asking what works, we must look at how to build systems that can continuously learn, adapt and invest resources where they’ll have the greatest long-term impact.
What real progress looks like — and why it takes time
For Teixeira, success isn’t just better programs. It’s fewer people becoming homeless, earlier intervention when risks emerge and shorter, less frequent experiences of homelessness. Ultimately, ending homelessness requires shifting from managing crises to preventing them in the first place.
But progress is rarely linear. Even when evidence is clear, change can be slow.
To illustrate that, Teixeira pointed to medicine. In 19th-century Vienna, a doctor named Ignaz Semmelweis discovered that handwashing dramatically reduced deaths in maternity wards. The results were immediate. Acceptance was not. It took decades for the practice to spread.
The same dynamic applies here. Evidence can show what works, but systems, behaviours and public attitudes take time to shift.
That’s why progress is cultural as well as technical. It depends on moving beyond silos and recognizing homelessness as a shared responsibility.
It also depends on public understanding. Large-scale campaigns have reshaped behaviours around issues like smoking, combining messaging, policy and changes to the built environment. A similar approach could shift how homelessness is understood — not as an individual crisis but as something shaped by systems and, therefore, preventable.
That work extends beyond governments and service providers, said Teixeira. Community networks, sports organizations and faith groups all have a role to play in reaching people where they are, and in reshaping how responsibility is shared.
“Doing good, better” is about turning knowledge into action across all these layers at the same time. It’s complex work. But as Teixeira reminded the audience, quoting Nelson Mandela, “It always seems impossible until it’s done.”
About the event
Teixeira’s visit was part of the Collaborative International Series on Innovation in Housing and Homelessness, an initiative that brings world-leading researchers to Ottawa and connect international and Canadian evidence with local action on pressing challenges.
The series is supported by the Office of Public Policy Research and Outreach (OPPRO) and the Alex Trebek Forum for Dialogue, part of the Office of the Vice-President, Research and Innovation. The OPPRO helps the University of Ottawa develop effective solutions to complex policy challenges and inform public policy in Canada and around the world.
The series is presented by the uOttawa Pop-Up Lab on Housing and Homelessness and the Centre for Research on Educational and Community Services (CRECS) in partnership with the office of Ottawa city councillor Stephanie Plante and the Alliance to End Homelessness Ottawa.