Intervention (Hidden)
Political affiliation conditions. In Wave 1 (before the first-round election on May 31, 2026), four conditions are active: the main right-wing establishment candidate (Candidate 1), a right-wing outsider candidate (Candidate 2), the main left-wing candidate (Candidate 3), and a no-photo control. These were the three candidates most likely to reach the runoff. Signaling both right-wing profiles ensures that one condition matches the eventual right-wing finalist regardless of the first-round outcome. Because two of the four conditions are right-wing, we assign probabilities that equalize the Left, Right, and Control cells in expectation: Candidate 3 receives probability 1/3, Candidates 1 and 2 each receive 1/6, and the no-photo control receives 1/3. In Wave 2 (June 1 to August 21, 2026), the three remaining conditions (the two finalists and the no-photo control) are each assigned with probability 1/3. The no-photo condition uses WhatsApp’s default blank profile picture. The runoff takes place on June 21, 2026, in the middle of Wave 2, creating two sub-periods: one between the first round and the runoff, and one after the runoff result is known.
Other treatment dimensions. Four additional attributes are randomized independently with equal probability (50/50): name class (high vs. low, signaled through first and last names), accent class (high vs. low, via a voice note), neighborhood belonging (prior connection vs. interest only), and applicant gender (female vs. male).
Validation of class signals. First and last names were selected and validated in a two-step procedure. In the first step, we used administrative data (the Gran Encuesta Integrada de Hogares, GEIH, and school enrollment records) to identify name combinations empirically associated with different socioeconomic strata in Colombia. Second, respondents in a dedicated pre-experiment survey in Bogotá rated the perceived social class of each full name; we retain only the names respondents most consistently classified into the intended category. Accents were validated in parallel: natural voice actors recorded otherwise identical rental inquiries in higher- and lower-class speech styles, and the same survey respondents rated the perceived social class of each recording. Only the recordings most consistently classified into the intended category are used in the experiment.
Outcome coding. The primary outcome is effective response: a binary indicator equal to 1 if the landlord directs the applicant toward the property (confirms availability, offers a visit, or provides follow-up contact) within seven days of the inquiry. Secondary outcomes are: any response received (a descriptive check); quality of response (coded by human coders on a structured rubric and cross-validated with an AI tool, with human-coder fixed effects); word count of the landlord’s reply; response time, measured both as elapsed hours from the applicant’s first message to the landlord’s first reply and as categorical thresholds set blind to treatment; and the number of exchanges required to obtain an effective response (tenant search burden).
Neighborhood political context. Each property is matched to 2026 presidential electoral returns at four spatial scales: locality (localidad), urban planning zone (UPZ), Google Maps neighborhood boundary, and nearest polling place (by Euclidean distance). At each scale, the local political orientation is defined as either a binary winner-takes-all classification (right vs. left, based on the second-round outcome) or a continuous vote-share gap between right-wing and left-wing candidates. We treat the full set of spatial scales and both orientation definitions as a pre-specified family, reporting estimates across all of them. The binary measure at the nearest polling place serves as the benchmark for power calculations.
Neighborhood amenity context. We define high-amenity neighborhoods as those where renters are willing to pay a high premium above what observable characteristics alone would predict. We measure this premium through neighborhood fixed effects from a hedonic housing price model estimated on the full universe of rental listings scraped prior to the experiment, controlling for property characteristics, time effects, access to employment and transport, and neighborhood quality indicators including socioeconomic stratum, proximity to parks, transit, commercial activity, schools, health services, cultural amenities, public safety, and environmental quality. Amenity status is defined both as a binary high-versus-low classification and as a continuous standardized index. We report heterogeneous treatment effects across this measure and alternative spatial scales, treating them as a pre-specified robustness family.
Pooling and wave structure. Our main analysis pools applications from both waves, with wave fixed effects in all specifications. We also estimate heterogeneity across three pre-specified electoral stages: (i) pre-first-round (May 4–30), (ii) between the first round and the runoff (June 1–20), and (iii) post-runoff (June 22–August 21).
Multiple hypothesis correction. Two outcome families are pre-specified: the set of main outcomes (effective response, quality, length, response time, and number of interactions to effective response) and the set of political signal × neighborhood interaction terms. We apply corrections for multiple testing within each family.