How Documentation—Not Just Protest—Won Tenant Concessions in São Paulo and Buenos Aires
By Teresa Villanueva
The first time a tenant organizer in São Paulo showed me his caderno, I didn’t understand what I was looking at. A school notebook, the kind you grab at any papelaria for three reais. Spine held together with packing tape. Pages gone soft from handling. Inside, the handwriting shifted between three or four people—because it had been three or four people, over six years, recording every violation their landlord committed. The month the elevator broke and sat dead for eleven weeks. The water shutoffs without notice. Rent increases that arrived without the legally required ninety-day warning. The tenant illegally charged a taxa de condomínio that never showed up in the building’s actual expense accounting.
This notebook was not archival. Not a record for posterity. It was a weapon. When the tenants’ association filed a collective complaint with the municipal housing secretariat, the notebook became their evidence. When a sympathetic public defender took the case, it became the backbone of the legal filing. When a city councilmember who had been ignoring their calls suddenly needed tenant organizations to endorse a housing bill, the notebook became the leverage that bought them a seat at the table.
Protest got the meeting. Documentation won the concession.
I’ve seen this pattern across Latin America, and now increasingly in U.S. cities where tenant movements are rebuilding after decades of organized labor’s collapse in the housing sector. The campaigns that produce binding outcomes—rent freezes, anti-harassment ordinances, zoning changes, eviction moratoria—are almost never the ones with the largest marches or the most viral moments. They are the ones where organizers spent years building what I’ve come to call documentation infrastructure: the systematic, governed, durable collection of evidence that turns individual complaints into structural arguments.
What follows is a comparative case study of two such systems. One was built in São Paulo’s central neighborhoods, using notebooks and later spreadsheets, by tenant associations that predated smartphones. The other was built in Buenos Aires, where a tenant union spent a decade collecting lease data to challenge the Argentine government’s official narrative about housing supply. Both produced policy concessions that protest alone had not. Both also reveal a tension movements everywhere now confront: how do you build documentation systems durable enough to survive volunteer turnover, platform instability, and funding cycles—without turning community data into an extractive academic dataset or a surveillance risk?
The São Paulo Notebook System
The central districts of São Paulo—Bela Vista, Sé, República, Pompéia—have some of the oldest residential tenancy stock in the city. Many buildings date to the 1950s and sixties, and their tenants are disproportionately elderly, low-income, and living under rent conditions the 2010 Urban Lease Law (Lei do Inquilinato) was supposed to regulate. In practice, landlord violations are routine. Illegal rent increases above the IPCA inflation index. Suppressed taxa de condomínio accounting. Failure to perform structural repairs. Harassment of rent-controlled tenants to push them out before units can be re-rented at market rates.
The União dos Movimentos de Moradia (UMM) and smaller neighborhood-based tenant associations in these districts began building what organizers internally called the sistema de cadernos—the notebook system—well before anyone used digital tools to track housing violations. The design was simple. The practice was demanding. Each building with an active tenants’ association designated one person, sometimes two rotating, as the relator: the person responsible for keeping the ledger. The relator recorded every violation in a standard format—date, category (rent, maintenance, harassment, utilities, other), description, witnesses, and whether any formal complaint was filed and with whom.
The format mattered less than the discipline. What made the notebook system effective was not sophistication but continuity. A building with three years of continuous violation records could walk into Defensoria Pública with a pattern of harassment no individual complaint could establish. A building with six months of records had a complaint. The difference between a complaint and a pattern is the difference between an individual grievance and a policy argument.
By the early 2010s, several associations had begun migrating notebooks to shared spreadsheets. Some used early versions of collaborative platforms. The migration was uneven and, in certain cases, destructive. One association I worked with lost two years of records when a volunteer’s personal Google account was deactivated after they left the organization and no one had transferred file ownership. Another discovered their spreadsheet had been silently edited by a former member who disagreed with current leadership—and they had no version history to prove what had been changed.
The notebook system’s most important lesson is not about tools. It is about organizational discipline—documentation as shared responsibility, not individual heroic act. The relator system worked because it was a role, not a personality. When one person left, another took over the notebook. The records belonged to the association, not to whoever happened to write them down.
Buenos Aires: A Decade of Lease Data
In Buenos Aires, the challenge was different, but the principle was the same. The Sindicato Único de Inquilinos (SUI), founded in 2015, began with a question no government agency seemed able to answer: how many tenants in the city were actually paying the rents that official housing reports said they were paying?
The Argentine government’s housing shortage reports, produced by the Instituto Nacional de Estadística y Censos (INDEC), relied on census data and landlord-reported rental values. Anyone who had ever rented an apartment in Buenos Aires knew these numbers were fiction. Landlords routinely required tenants to sign two contracts—one for the official amount, one for the actual amount, paid in cash or bank transfer with no receipt. Security deposits were almost never returned without legal action. Garantes—guarantors who co-signed leases and whose own properties were listed as collateral—were required even when the law did not mandate them, creating an invisible income filter that locked out anyone without a property-owning family member.
The SUI built its own dataset. Over ten years, they collected lease terms from more than 4,000 tenants across the city’s forty-eight barrios, using a standardized intake form that volunteers administered in person—at neighborhood assemblies, community centers, door-to-door canvasses. The form captured what official data did not: actual rent paid versus contract rent, deposit amount and whether it was returned, garante requirements, informal fees, duration of tenancy, reason for departure.
The dataset was not perfect. It was a convenience sample, not a random one, and organizers knew this. But it was the only dataset that reflected actual tenant experience rather than landlord-reported figures. When the SUI published their first analysis in 2019, showing that real median rents in working-class neighborhoods were 40-60% higher than INDEC’s reported medians for the same areas, the city’s housing secretariat could not dismiss it. The data was too specific, too internally consistent, too deeply tied to named tenants willing to testify.
The SUI’s documentation work produced three concrete policy concessions between 2019 and 2023. First, the city legislature passed an anti-harassment ordinance creating penalties for landlords who engaged in the specific behaviors the SUI had documented most frequently: repeated unannounced visits, utility shutoffs, refusal to accept rent payment in order to claim default. Second, the Buenos Aires housing secretariat established a tenant assistance program modeled on the SUI’s intake process, using a version of their form. Third, the SUI’s data became a reference point in the national debate over lease reform. When Congress modified the Ley de Alquileres in 2020, several provisions—including extension of minimum lease terms from two to three years—were directly informed by evidence the SUI had gathered about how short-term leases were used to circumvent rent stabilization.
None of this happened because of a protest. Protests happened, and they mattered. But the concessions came because the SUI could walk into a legislative hearing and say: here are 4,000 lease records, here is the methodology, here is the gap between official data and actual data, and here are the tenants who will testify.
The Central Tension: Durability Without Extraction
Both the São Paulo notebook system and the Buenos Aires lease dataset reveal a tension every movement building documentation infrastructure must confront. Documentation systems need to be durable—surviving volunteer turnover, platform changes, organizational splits, funding cycles. But durability introduces risks. The more comprehensive and permanent your documentation, the more valuable it becomes to actors who do not have your community’s interests at heart: landlords seeking to identify troublemaker tenants, developers mapping neighborhoods for acquisition, academic researchers who treat community data as raw material for their own publications, state agencies that may use your records to justify interventions your community never asked for.
The São Paulo relator system partially addressed this by keeping documentation physical—held by the association, accessible only through the organization’s governance structure. The notebook did not live in the cloud. It could not be scraped. But it also could not be easily shared, backed up, or analyzed at scale. When the association needed to produce a report for the Defensoria Pública, someone had to manually transcribe the relevant entries. When the relator left, the notebook stayed—but the institutional knowledge of how it was organized, what the abbreviations meant, which entries had been followed up on, sometimes did not.
The SUI faced a different version of the same problem. Their dataset was digital, which made it analyzable and shareable. But digital data is also more vulnerable: to platform instability, unauthorized access, the risk that a funder or partner organization might demand access as a condition of support. The SUI had to develop internal governance rules about who could see raw data, who could see aggregated data, under what conditions data could be shared externally. They also had to decide what happened to the data if the organization dissolved—a real question for any movement organization dependent on volunteer labor and short-term funding.
These challenges map onto fields movements rarely look to for guidance. Site reliability engineering, for instance, has developed a substantial body of practice around tracking incidents, maintaining data integrity across contributor turnover, and building a postmortem culture that documents failures without creating blame—concepts that translate directly to movements tracking eviction patterns and landlord violations over years. The Google SRE book, particularly its chapters on tracking outages, postmortem culture, and data integrity, offers a framework for thinking about documentation systems that persist beyond individual contributors while remaining trustworthy and governed.
Similarly, governing sensitive community data—deciding who has access, how it is protected, what happens when the organization’s structure changes—requires the kind of explicit risk management framework cybersecurity practitioners formalize. The NIST Cybersecurity Framework provides governance principles for managing sensitive data that can inform how movements design protective controls around tenant violation ledgers, lease datasets, and oral history registries, ensuring documentation infrastructure serves the community rather than becoming a tool that can be turned against it.
A Tactical Framework for Community Documentation Pipelines
Drawing from both cases and the broader principles of durable, governed systems, here is a framework for designing community documentation infrastructure. I offer it not as a template but as a set of decision points each organization must work through in its own context.
1. Define the documentation’s purpose before its form. The São Paulo notebooks existed to establish patterns of landlord violations for legal and administrative complaints. The Buenos Aires dataset existed to challenge official housing statistics. Both purposes dictated what was collected, how, and by whom. Before you build any documentation system, answer: what specific policy or legal outcome is this documentation intended to produce? If you cannot answer that question, you are building an archive—which is valuable, but it will not win you policy concessions.
2. Assign documentation as a role, not a personality. The relator system worked because the role was defined, rotating, embedded in the association’s governance structure. When documentation depends on one committed person, it dies when that person leaves or burns out. When it is a role with clear responsibilities, handoff procedures, accountability to the organization, it survives. Write the role description down. Include what is documented, how often, where records are stored, who has access.
3. Choose tools based on your threat model, not your funders’ preferences. If your primary risk is platform instability and organizational turnover, physical notebooks and locally stored spreadsheets may be more durable than cloud platforms requiring active account management. If your primary risk is physical loss or seizure, encrypted digital storage with distributed backups may be necessary. If your primary risk is surveillance by landlords or state agencies, you need a different set of controls than if your primary risk is academic extraction. Do not let a funder’s preference for a particular platform dictate your documentation infrastructure. The tool serves the threat model, not the grant report.
4. Establish data governance rules before you have data worth governing. Decide in advance: who has access to raw data? Who can see aggregated data? Under what conditions can data be shared with external partners, researchers, government agencies? What happens to the data if the organization dissolves? What consent process do contributors—tenants, community members—go through when their information is recorded? The SUI’s governance rules—raw data visible only to designated members, aggregated data shareable with attribution, external sharing requiring organizational vote—were developed early enough that they were institutional before any crisis tested them.
5. Build redundancy without building dependency. The notebook system had redundancy: multiple relatores knew the system, notebooks were physically stored in the association’s meeting space with copies held by two members. But it did not have dependency: no single platform, tool, or external partner controlled access to records. When you choose documentation tools, ask: if this platform disappeared tomorrow, would we still have our data? If this partner pulled out, could we still maintain our records?
6. Document your documentation system. This sounds recursive. It is the most common failure point. The São Paulo associations that lost institutional knowledge when relatores left did not lose the notebooks—they lost knowledge of how the notebooks were organized. Write down the system itself: the intake form, the categories, the filing structure, the access rules, the handoff procedures. This meta-documentation should live in multiple formats and locations. Review and update it at least once a year with whoever currently holds the documentation role.
What Movements Lose When Documentation Fails
The cost of not building documentation infrastructure is measured in concessions not won. I have watched tenant associations in Mexico City present passionate, well-attended testimony at housing hearings with no underlying data to back their claims—and watched councilmembers politely thank them and vote for the developer-friendly version of the ordinance. I have seen eviction defense campaigns in Los Angeles that saved individual families but produced no systemic record of the displacement patterns they witnessed, meaning the next campaign in the same neighborhood started from zero.
Documentation is also what separates movements that learn from their own history from those that repeat it. The São Paulo tenant associations that maintained notebooks across multiple administration changes could tell new members: this landlord has been doing this since 2009, here is the pattern, here is what we tried last time, here is what worked and what didn’t. The associations that did not maintain records had to relearn the same lessons every time leadership turned over. Organizational memory without documentation is storytelling. With documentation, it becomes strategy.
There is also a practical question of how movements manage the sheer volume of records, meeting notes, and violation logs they accumulate. Some organizations I work with have begun experimenting with structured drafting tools—an AI writing software that helps their members turn raw documentation into formatted policy briefs—though the governance question of what data goes into any external tool remains live and unresolved in most groups I know. The point is not the specific tool but the principle: documentation that cannot be synthesized into arguments is documentation that cannot change policy. The pipeline must run from the notebook to the hearing room, and every step in between must be governed by the community that collected the data.
The Difference Between Symbolic and Structural Victories
São Paulo’s notebook system contributed to the municipal housing secretariat’s adoption of a landlord violation registry in 2018—a structural outcome that outlasted any single administration. Buenos Aires’s lease dataset contributed to national lease reform and a city-level anti-harassment ordinance—structural outcomes that changed the legal framework within which landlords operate. Both were won because organizers understood that protest creates political pressure but documentation creates policy evidence, and policy evidence is what forces concessions that survive beyond the news cycle.
The notebook and the dataset are not glamorous. They will not be photographed for movement documentation the way a march or an occupation will. But they are what makes the difference between a movement that is heard and a movement that is answered. When I think about that caderno held together with packing tape, I think about six years of a community’s refusal to be invisible—written down in shifting handwriting across soft pages. That refusal won them their seat at the table. Protest is how you demand to be heard. Documentation is how you ensure that what you say cannot be denied.
The movements that will win the next decade of housing struggles in Latin American and U.S. cities will not be the ones with the most followers or the most dramatic actions. They will be the ones that built the infrastructure to remember what happened to them—and to prove it.
