Politics of Food: Additional Study

Participants are randomized into one of four treatment groups: TRUMP, BIDEN, CONTROL, or PURE CONTROL.

Participants in the PURE CONTROL group only complete the demographics section of the survey and do not receive any further information. Everyone else begins the study by learning about citrus greening disease and the damage that it has caused to citrus crops throughout the United States. Furthermore, the participants are told about a policy of applying large quantities of antibiotics on citrus crops to combat the disease in the United States.

Participants in both the TRUMP and BIDEN groups learn about the opposition to the policy, including arguments made by issue advocacy groups that focus on increasing antibiotic resistance and direct effects of exposure.

This is followed by information about the Environmental Protection Agency’s (EPA’s) authorization decision to allow streptomycin spraying.

In the TRUMP group, we highlight the Trump administration’s support for the authorization and we state that “the EPA under the administration of President Donald Trump provided arguments and scientific evidence supporting the position that antibiotic spraying of citrus crops poses little risk and ‘meets the regulatory and safety standards.’ We also provide a photo of Donald Trump shaking hands with his EPA head appointee.

The BIDEN treatment is identical to the TRUMP treatment, except that we replace all mentions of Trump with Biden and provide the photo of Biden shaking hands with his EPA head appointee.

On the next screen, we provide a list of specific arguments made by EPA’s scientists in favor of the policy. The arguments do NOT vary by treatment. The photo of the relevant president (the same photo as in the previous screen) is shown on the page.

Participants in the CONTROL group do not see information on the opposition to the policy and the EPA’s final authorization, including the scientific arguments.

2025-10-21

2025-11-15

First survey:

1. Heterogeneity of treatment effects on the policy support index, trust index, and planned consumption of citrus products by baseline level of trust in regulatory agencies (including the EPA).

Follow-up survey:

2. Familiarity with EPA regulation that allows using antibiotics on citrus crops to fight plant disease.

3. Knowledge of president in office at time of EPA regulation enactment.

4. Trust in EPA regulation on using antibiotics on citrus crops to fight plant disease.

RE 1:

Outcome definitions:

The policy support index is based on participants’ agreement (on a scale from 0 to 100) with four statements, two of which imply agreement with the policy and two indicating disagreement. The statements are as follows:
1) The policy is safe as it is endorsed by the relevant government agency.
2) The policy has negative consequences on people's health.
3) I think that antibiotic spraying of citrus crops should be outlawed.
4) I support the policy as it helps protect the economy with no major risks involved.

To construct the index, we first standardize agreement scores for each statement. Then, the scores for statements that indicate disagreement are multiplied by −1. Lastly, we compute the sum of the sign-adjusted standardized scores.

The trust index is based on participants’ agreement (on a scale from 0 to 100) with four statements, two of which imply trust in EPA’s arguments and two indicating lack of trust. The statements are as follows:
1) I trust the EPA which determined that the policy is safe.
2) The arguments provided by the opponents of the policy were convincing.
3) The scientific evaluation conducted by the EPA was thorough and I trust it.
4) The opponents of the policy are scaremongering.

To construct the index, we first standardize agreement scores for each statement. Then, the scores for statements that indicate less trust are multiplied by −1. Lastly, we compute the sum of the sign-adjusted standardized scores.

To measure the planned consumption of citrus products, we ask participants about the likelihood (0-100) of purchasing orange-based products (such as orange juice) or other citrus-based products in the upcoming month.

Baseline trust:

We use the following question to measure baseline trust in regulatory agencies.

What is your overall level of trust in each of the following agencies and departments of the federal government? (Very low trust, Somewhat low trust, Somewhat high trust, Very high trust)

1) Environmental Protection Agency (EPA),
2) Food and Drug Administration (FDA),
3) Federal Reserve,
4) National Park Service,
5) Centers for Disease Control and Prevention (CDC).

Very low trust is coded as 1, Somewhat low trust as 2, Somewhat high trust as 3, and Very high trust as 4. When conducting the heterogeneity analysis, we use two approaches: (a) we focus exclusively on baseline trust in the EPA, (b) we focus on the sum of trust scores for all of the five agencies listed above.

RE 2:

We use the following question to measure familiarity with regulations.

How familiar are you with the following rules or regulations issued by federal agencies? (0-100 slider)
1) FCC rules on equal treatment of internet traffic (net neutrality).
2) FDA rules on food nutrition labels.
3) EPA regulation that allows using antibiotics on citrus crops to fight plant disease.
4) CMS regulation that requires hospitals to post prices for services online.

We are only interested in statement 3 "EPA regulation that allows using antibiotics on citrus crops to fight plant disease." The remaining questions are decoy questions. We are primarily interested in the comparison between TRUMP + BIDEN groups combined against PURE CONTROL and TRUMP + BIDEN groups combined against CONTROL.

RE 3:

In the previous question, you saw the EPA regulation that allows using antibiotics on citrus crops to fight plant disease listed as an example. To the best of your knowledge, during whose presidency were these rules first issued?
1) George H. W. Bush
2) Bill Clinton
3) George W. Bush
4) Donald Trump
5) Joe Biden

We are interested in comparing the share of respondents who answered "Donald Trump" in TRUMP vs. PURE CONTROL groups. Similarly, we are interested in comparing the share of respondednts who answered "Joe Biden" in BIDEN vs. PURE CONTROL groups.

RE 4:

Consider the previously mentioned example of the EPA regulation that allows the use of antibiotics on citrus crops to fight plant disease.

To what extent do you agree with the following statements about the scientific analysis the EPA conducted before issuing the regulation? (0-100 slider)

1) I trust the EPA which determined that the policy is safe.
2) The scientific evaluation conducted by the EPA was thorough and I trust it.

To construct the index, we first standardize agreement scores for each statement. Then, we compute the sum of the standardized scores.

Follow-up survey

1. Confidence in regulatory agencies

RE 1:

On a scale from 0 to 100, where 0 means 'no confidence at all' and 100 means 'complete confidence,' how much confidence do you personally place in each of the following federal agencies?
1) Environmental Protection Agency (EPA),
2) National Aeronautics and Space Administration (NASA),
3) U.S. Postal Service (USPS).

We analyze this outcome in two ways. First, we specifically report treatment effects on confidence in the EPA (statement 1). Second, we report treatment effects on the index of trust based on statements 1-3. To construct the index, we first standardize agreement scores for each statement. Then, we compute the sum of the standardized scores.

We recruit participants on Prolific. We restrict the pool of eligible participants to those who answered "Democrat" on the Prolific's US political affiliation question. Participants are required to complete a 15-minute Qualtrics survey about a public policy issue. The survey begins with demographic questions. As a part of this section, we elicit consumption and purchases of three basic products (milk, bread, orange juice) during the past month. We separately ask participants to indicate if, in general, they never consume any of these products. We classify people as OJ NEVER CONSUMERS if they answered that they did not purchase or consume orange juice in the last month and that they generally do not buy orange juice. Everyone else is classified as OJ CONSUMERS. Importantly, the demographics section includes a question eliciting baseline level of trust in multiple regulatory agencies.

Participants are randomized into one of four treatment groups: TRUMP, BIDEN, CONTROL, or PURE CONTROL. Random assignment of treatment is performed separately for OJ CONSUMERS and OJ NEVER CONSUMERS. In both cases, the probability of being assigned the TRUMP group and the BIDEN group is 1/3, whereas the probability of being assigned the CONTROL group and the PURE CONTROL group is 1/6.

Participants in the PURE CONTROL group only complete the demographics section of the survey and do not receive any further information. Everyone else begins the study by learning about citrus greening disease and the damage that it has caused to citrus crops throughout the United States. Furthermore, the participants are told about a policy of applying large quantities of antibiotics on citrus crops to combat the disease in the United States.

Participants in both the TRUMP and BIDEN groups learn about the opposition to the policy, including arguments made by issue advocacy groups that focus on increasing antibiotic resistance and direct effects of exposure.

This is followed by information about the Environmental Protection Agency’s (EPA’s) authorization decision to allow streptomycin spraying.

In the TRUMP group, we highlight the Trump administration’s support for the authorization and we state that “the EPA under the administration of President Donald Trump provided arguments and scientific evidence supporting the position that antibiotic spraying of citrus crops poses little risk and ‘meets the regulatory and safety standards.’ We also provide a photo of Donald Trump shaking hands with his EPA head appointee.

The BIDEN treatment is identical to the TRUMP treatment, except that we replace all mentions of Trump with Biden and provide the photo of Biden shaking hands with his EPA head appointee.

On the next screen, we provide a list of specific arguments made by EPA’s scientists in favor of the policy. The arguments do NOT vary by treatment. The photo of the relevant president (the same photo as in the previous screen) is shown on the page.

Participants in the CONTROL group do not see information on the opposition to the policy and the EPA’s final authorization, including the scientific arguments.

The last screen before outcome elicitation, shown to participants in all groups except the PURE CONTROL, contains a map of the US with four states responsible for almost all commercial citrus production highlighted (according to USDA report). Participants are reminded that “the policies allowing the application of antibiotics on orange crops remained in force in Florida as of August 2025.”

We first elicit support for the policy of anibiotic spraying using the policy support index. Subsequently, participants in TRUMP and BIDEN groups complete the trust index, which is a series of questions about their trust in EPA’s arguments about the safety of streptomycin spraying. This is followed by a question about planned citrus product consumption (including in the CONTROL group).

Participants classified as OJ CONSUMERS will be invited to complete an obfuscated follow-up survey focused on political knowledge. The survey begins with a decoy section consisting of questions about familiarity with various Congressional acts, followed by items asking respondents to identify during whose presidency different acts were passed. The second section focuses on regulatory agencies and includes questions about familiarity with specific regulations, such as FCC rules on equal treatment of internet traffic, FDA rules on food nutrition labels, the EPA regulation permitting the use of antibiotics on citrus crops to combat plant disease, and the CMS rule requiring hospitals to post service prices online. For two of these regulations, including the EPA regulation, participants are also asked to identify during whose presidency they were enacted. Moreover, this section includes items assessing confidence in three agencies (EPA, NASA, and USPS) as well as trust in the specific EPA regulation allowing antibiotic use on citrus crops.

Qualtrics randomization

Individual

No

N/A

We plan to recruit a total of 1,050 individuals to complete the first survey. This total includes 446 participants recruited during a pilot phase (prior to pre-registration) and 604 participants to be recruited following pre-registration. We will pool both samples to maximize statistical power.

We expect approximately 350 individuals in TRUMP group, 350 individuals in BIDEN group, 175 individuals in CONTROL, and 175 individuals in PURE CONTROL to complete the first survey.