We fielded the survey experiment between March 1-13, 2021 to a sample of 2,508 Colombian adults who were at least 18 years old.<sup>10</sup> These respondents came from a larger online panel of approximately 140,500 respondents.<sup>11</sup> Our sampling aimed to be representative across different dimensions of the country’s population based on the 2018 Colombian census, including key demographic variables including age, gender, region, and socioeconomic _strata_ (a measure of income used in Colombia). Table A4, which displays the distributions of these variables in our sample against those from the 2018 census, indicates how our sample shows close similarity with the census estimates.<sup>12</sup> We also recorded additional socio-demographic and economic variables for the respondents. Description and descriptive of other additional features of our sample appear in the Appendix <u>(Table A5).</u> Since each respondent saw five pairs of policy packages, our analysis comprises 25,080 observations.

# **4.3 Estimation Strategy**

We analyse the data in three steps. First, we estimate both the average marginal component effects (AMCEs) and marginal means (MMs) to measure public preferences towards each policy option within each dimension. AMCEs report a series of linear probability estimations where the dependent variable is a binary (forced choice) variable indicating the preferred policy by the respondent. The dependent variable is regressed on the levels of each policy dimension (with a researcher-chosen reference category as the baseline level) to estimate the probability of respondents choosing that policy option in relation to the reference category. To test for the consistency of the results, we also use a scaled rating version as a dependent variable where the policy ratings are re-scaled to vary between 0-1 (see <u>Table A3</u> for a description). In all estimations, we report robust standard errors clustered at the respondent level since each respondent saw multiple treatments (Hainmueller et al. 2014).

> 10 The survey experiment was reviewed and approved by the Central University Research Ethics Committee (CUREC) of the University of Oxford (C1A-20-2) and the pre-analysis plan was registered with As-Predicted (#60418).

> 11 We worked with Invamer (https://www.invamer.com.co/), a reputable nationally recognised survey firm with one of the largest online panels in the country. They operated through the Netquest platform, and their recruitment strategy is based on incentives that are granted to the respondents at the end of the survey.

> 12 Nevertheless, we acknowledge that our use of online sampling might have over-represented individuals with online access and sufficient digital literacy to access an online survey—who in turn may have been more educated and urban-dwelling within broad regions. For context, in terms of internet access, Colombia ranks in the middle of other Latin American countries of similar income levels: according to World Bank estimates, 65% of the population in the country has access to use the internet. This is higher than Ecuador (54%), Peru (60%), and Bolivia (44.2%), but lower than Mexico (70%), Argentina (74%), and Brazil (70%) [https://data.worldbank.org/indicator/IT.NET.USER.ZS].

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