Design of the survey questionnaire consisted of the following steps: (i) Three 2.5-hour exploratory focus group discussions about public attitudes and comprehension of agricultural applications of gene drive insects were conducted with a total of 21 primary grocery shoppers recruited at grocery stores in Durham, Raleigh, and Dunn, North Carolina in spring 2017 [note S5; 53)]; (ii) using analysis of the focus groups, we drafted the survey instrument in Qualtrics and initially pretested with students and colleagues in North Carolina State’s Genetic Engineering and Society Center (which encompasses many social and natural science disciplines and includes a broad range of opinion on novel biotechnologies); (iii) we revised the Qualtrics instrument and further pretested it with Amazon Mechanical Turk (n = 300) to gather qualitative feedback on information frame presentation, comprehension, and design; (iv) we further revised the Qualtrics instrument to address open-ended feedback in pretests, adhere to KnowledgePanel requirements and reduce median completion time to 25 min or less, and implement a final experimental design of BWS subsets; and (v) we launched the finalized the survey instrument with a KnowledgePanel sample.

After a brief introduction and informed consent, the survey instrument contained the following sections analyzed in this paper (presented in this order): (i) respondent consumer characteristics; (ii) general textual and visual information about how gene drives work, followed by description of the potential applications of a spotted wing Drosophila repression drive and a Asian citrus psyllid replacement drive; (iii) FAQs; (iv) BWS exercise on gene drive uncertainties; (v) respondent knowledge of current organic certification requirements; (vi) views on allowing gene drives within organic certification; (vii) elicit support/opposition to the eight types of gene drives in Fig. 1; and (viii) religiosity, elicited at the end to avoid any impacts (e.g., due to saliency or availability bias) of this question on preceding responses.

Note: Respondents were asked whether they support or oppose the use of gene drives to control agricultural insect pests in each of eight applications. (A) Condensed Likert response frequencies varying (i) whether the drive would reduce populations or alter populations to not carry a crop disease, (ii) whether controls are in place to limit the extent of drive spread, and (iii) whether the target species was native to an area. (B) 95% confidence intervals (CIs) shown for average marginal effects of estimates from a pooled ordered logit model with SEs clustered by respondent (full model tables 2 and 3, inclusion of respondent covariates in Table 1).

Note: Level of support and opposition to gene drive insect applications for seekers and nonseekers non-GMO–labeled food [95% CIs shown; suppression and replacement applications combined (see table S6)]. While those searching for non-GMO–labeled food are relatively less supportive and more likely to explicitly oppose drive applications (Table 1), a slight majority (53%) still support applications in non-native species with controls for drive spread with 26% opposing.

Note: Level of agreement (with 95% CI) that a farmer should be able to retain organic certification in the presence of gene drive insects, among affirmed regular purchasers of certified organic food products (n = 228), by whether the respondent is aware that some types of insecticides are allowed under organic regulations (57% of regular organic consumers aware). Questions are asked separately by whether (A) gene drive insects are used in the area to control a damaging insect species or (B) that use of drive insects in results in genetically modified insect material “getting in or on crops.” **P < 5% and *P < 10% for adjusted Wald tests of equivalent response means.

Note: (A) FAQ selection. Voluntary respondent selection frequency from the seven-item FAQ list. Question wording is abbreviated for exposition; see the Supplementary Materials for the complete survey text. (B) Ranking uncertainties to resolve before use decisions. Respondents selected the “most important” and “least important” among iterative four-item subsets of the 10 alternatives to resolve “before deciding whether gene drive insects should be used to control pest damage to crops” (numbers denote statistical ranking via weighted least-squares regression and Wald tests of linear hypotheses; full item wording is found in note S4, WLS model results are found in table S7, and an example choice scenario is found in fig. S1).

Note: Respondents indicated “how trustworthy [they] feel each type of institution would be conducting research on gene drive insects to control agricultural pests” (full question wording and raw data is found in table S8).

Part (i) included relevant respondent characteristics not automatically collected in the KnowledgePanel, described below. The information provision in (ii) began with the following consequentiality statement, to retain attention and to reduce hypothetical bias (54): “Your responses to questions about this information will inform policy decisions at the US Department of Agriculture.” The full informational text and illustrations for (ii) are in note S1. Wording of the FAQs in (iii) is in note S2; these FAQs were crafted on the basis of focus group findings, open-ended feedback on survey pretests, and a previous FAQ webpage published by the Wyss Institute at Harvard ( Respondents could select as many as they wished to view (including none), with presentation order randomized to avoid order effects. Each unselected FAQ was still shown to respondents with one-third probability. In table S10, we used an instrumental variable (IV) linear regression model with random forced assignments to view each FAQ as IVs to verify that viewing specific FAQ items did not significantly impact subsequent attitudes on gene drives (P = 0.37 for joint test of all FAQ items, process described further in the “Statistical Analysis” section).

The BWS exercise in (iv) followed methods in (28, 29); this survey methodology was selected because of its lower cognitive demand and faster completion than elicitation of a full rank order, and as compared to a set of Likert scales, it avoids between-respondent scale differences and higher likelihood of ties. The exercise was preceded by the following instructions (further details in note S4 and example question in fig. S1):

“Many questions remain to be answered before deciding whether gene drive insects should be used to control agricultural pests. Policy makers want to know how the public feels about these issues and which research questions are most important to answer. We need your help to inform these decisions.

Here, we will show you a short series of questions. We would like to know which you feel is the ‘most important’ and which is the ‘least important’ to answer.”

The selection and wording of the uncertainties included in the BWS exercise were based on the 2016 NASEM report conclusions (6) combined with focus group and survey pretest feedback; note S4 describes this in detail. The experimental design of the BWS exercise followed a Balanced Incomplete Block Design to guide choice set construction (29). With 10 items to rank, the full design contained 15 sets of 4 items each, with each item occurring six times and co-occurring two times with each other item. The SAS software package (version 9.4, with macro %mktbibd) was used to identify a statistically efficient three-block design limited to five sets for each respondent to reduce survey fatigue and completion time. Respondents were randomly assigned to a block, and every respondent saw each item at least once. Choice set order, as well as item order within each choice set, was randomized to avoid order effects.

Knowledge of organic certification in (v) consisted of the single question, “Please indicate the extent to which you believe the following statement is true or false: Food that is certified ‘USDA organic’ can be produced applying certain types of insecticides [Image of USDA organic label shown].” Responses consisted of a scale ranging from “Definitely False,” “Probably False,” “Probably True,” to “Definitely True” and included a “Don’t Know” option. We defined “awareness” of pesticide allowances within organic certification, as used in Fig. 3, as selection of “Probably True” or “Definitely True.” In (vi), two questions on support for organic certification allowing gene drive insects (“in the area” for one question and “on or in the crops” for the second) were elicited on a five-point Likert scale ranging from “Strongly Disagree” to “Strongly Agree.”

Part (vii) elicited respondents’ levels of support or opposition to the eight possible combinations of three binary factors for gene drive insect applications: intended for suppression/replacement, self-limiting/unlimited spread, and native/non-native target species. These factors were chosen on the basis of the 2016 NASEM report recommendations (6) and related feedback from focus group participants. Particularly motivating was report recommendation 9-3: “The distinguishing characteristics of gene drives—including their intentional spread and the potential irreversibility of their environmental effects—should be used to frame the societal appraisal of the technology, and they should be considered in ecological risk assessment, public engagement, regulatory reform, and decision making” (6). The terminology for these factors was simplified to aid comprehension by respondents about these unfamiliar technologies. The description of these factors preceding this set of questions read as follows (emphases in instrument):

“After reading about gene drives for agricultural uses, we would like to hear how you feel.

Specifically, we want to know how you feel about gene drives to reduce populations of pests vs. to alter pests to prevent them from carrying a crop disease.

We also want to know how you feel about gene drives used on insects which are native to an area vs. insects which are not native to an area. (Note: both the berry and citrus pest examples are invasive species not native to the United States).

Finally, some scientists have proposed trying to control how far a gene drive can spread. We would like to know how you feel about gene drives when scientists try to limit how far a gene drive can spread vs. gene drives which are allowed to potentially spread to the global population of the insect species.”

Following this preamble, respondents were then asked for each of the eight applications: “Overall, to what extent would you personally support or oppose the use of gene drives to control agricultural insect pests in the following applications: …” [emphasis in instrument]. Support or opposition to each of the eight applications (randomizing their order) was assessed for every respondent, on a five-point scale from 1 = “Strongly Oppose” to 5 = “Strongly Support,” and including both a “Neither Support nor Oppose” and a “Don’t Know” option (aggregated together here, but tested in robustness).

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