Housing searches play a central role in the reproduction of racial inequality in U.S. cities. Past research finds that movers’ social ties influence residential segregation, as renters receive information about homes located near friends and family. Fewer studies examine how renters’ social ties also provide instrumental assistance during moves, or how this aid unequally shapes moving outcomes. In the present study, I show how 69 low-income, Latina/o and non-Hispanic white renters rely on their friends, family, and acquaintances to navigate moves in Los Angeles, a highly unaffordable rental market. Both groups mobilize their ties for instrumental assistance, but the resources available through renters’ ties contribute to diverging search outcomes. Low-income Latina/o renters’ ties, who also struggled to make ends meet, provided what I call constrained support—referrals to open units, loans to cover moving costs, and informal rental opportunities. This assistance channeled movers to specific apartments and left them negotiating informal, doubled-up homes and new debt. In contrast, low-income white renters leveraged comparatively affluent ties to cosign leases, provide financial gifts, and strengthen applications across buildings—what I refer to as flexible assistance. This aid helped low-income white movers secure housing advantages, while avoiding short-term reciprocal obligations to friends and family. These findings advance research on residential mobility and social support, and they show how network resource inequalities contribute to racial stratification in rental markets.

In many clinical settings, an active-controlled trial design (e.g., a non-inferiority or superiority design) is often used to compare an experimental medicine to an active control (e.g., an FDA-approved, standard therapy). One prominent example is a recent phase 3 efficacy trial, HIV Prevention Trials Network Study 084 (HPTN 084), comparing long-acting cabotegravir, a new HIV pre-exposure prophylaxis (PrEP) agent, to the FDA-approved daily oral tenofovir disoproxil fumarate plus emtricitabine (TDF/FTC) in a population of heterosexual women in 7 African countries. One key complication of interpreting study results in an active-controlled trial like HPTN 084 is that the placebo arm is not present and the efficacy of the active control (and hence the experimental drug) compared to the placebo can only be inferred by leveraging other data sources. In this article, we study statistical inference for the intention-to-treat (ITT) effect of the active control using relevant historical placebo-controlled trials data under the potential outcomes (PO) framework. We highlight the role of adherence and unmeasured confounding, discuss in detail identification assumptions and two modes of inference (point vs. partial identification), propose estimators under identification assumptions permitting point identification, and lay out sensitivity analyses needed to relax identification assumptions. We applied our framework to estimating the intention-to-treat effect of daily oral TDF/FTC versus placebo in HPTN 084 using data from an earlier Phase 3, placebo-controlled trial of daily oral TDF/FTC (Partners PrEP). Supplementary materials for this article are available online, including a standardized description of the materials available for reproducing the work.