Experimental Design Details
We will recruit participants through luc.id, an online platform which gathers a representative sample of the US population.
We assign participants to treatments using stratified random sampling. We define 18 strata, based on age (3 levels), political party (3 levels), and sex (2 levels). Within each stratum we perform a 3-step randomization of participants into one of two experiments, further into one of two treatment arms, and finally into one of several treatment variations.
In both experiments, the randomized portion of treatment consists of four distinct messages delivered in two doses of two messages. We deliver one dose of two messages and measure a first set of outcomes; then we deliver a second dose of messages and measure further outcomes. We randomize the order of these messages between one of 6 orderings in the Strong vs. Weak experiment and one of 2 orderings in the Steady vs. Changing experiment.
Within a stratum, each step of randomization is sequential based on arrival time and nested within the previous step. Among the first two participants to arrive in a stratum, exactly one will enter each experiment. Then, among the first two within each experiment, exactly one will enter each treatment arm. Finally, among the first six (in Strong/Weak) and first two (in Steady/Changing) in each treatment arm, exactly one will see each ordering of the treatments.
In the Strong vs. Weak experiment, we randomize participants to an information treatment about the extent of the federal government’s response to COVID-19 (stronger or weaker). For example, a participant in the strong response may be told that the Trump administration may use wartime powers to procure emergency medical supplies. We have four pieces of information in the “weak response” treatment and four pieces of information in the “strong response” treatment. In the Steady vs. Changing experiment, we randomize participants between information that does or does not highlight changes in government policy. In the Steady treatment arm, we provide participants with a piece of information that the federal government is taking a strong action against COVID-19. In the Changing arm, we provide the same information, but we also tell participants about the federal government’s prior response which differed from this strong action. Last, in both arms, we provide participants with information about the federal government’s prediction that there will be 100,000–240,000 deaths from COVID-19.
In both experiments, we solicit baseline knowledge and beliefs about the severity of the COVID-19 crisis in the US (in terms of health and economic effects) and the federal government’s response.
After the first dose of treatment, we record participants’ anxiety using a clinical anxiety measure (Beck Anxiety Inventory). In order to measure belief updating, we re-prompt participants to provide their knowledge and beliefs about the severity of the COVID crisis (in terms of health and economic effects). Next, we elicit demand for information by informing participants that we will provide them a link to an article on one of four subjects at the end of the survey: (i) cute animal pictures, (ii) information about COVID cases and deaths in the United States, (iii) information about the effect of the Senate CARES bill on health insurance coverage, and (iv) information about wellness and stress-reduction. After eliciting these outcomes, we then provide the remaining statements within the treatment group. In the Strong vs. Weak experiment, we provide another set of statements detailing strong (or weak) government actions. In the Steady vs. Changing experiment, we provide another example of Steady or Changing government action. Next, we elicit participants’ choice over a 50-50 lottery (where they receive either $0 or $30) vs. $15 for sure. The participants conduct a data entry task; in one task, they sort metropolitan areas by population, and in another task, they sort states by the number of positive COVID-19 tests in that state as of March 26. Participants are randomized into which data entry task they complete. We ask participants to provide other self-reports of possible concerns they may have about the coronavirus crisis, e.g. that it may cause them to get sick; the purpose of this exercise is to decompose why they may feel anxious. Following this elicitation, we conclude the survey by asking participants about the number of people they plan to see socially outside the household. The objective of this question is to determine whether the participant plans to adhere to social distancing guidelines.
We also elicit updates about participants’ views about the government reaction to the crisis. In the Weak vs. Strong experiment, we elicit these at the end of the study. In the Steady vs. Changing experiment, we elicit these after the second treatment dose. We elicit these directly after treatment in Steady vs. Changing because it is a primary outcome in that experiment.