Endogenous Screening and Health Behaviors

Last registered on November 25, 2025

Pre-Trial

Trial Information

General Information

Title
Endogenous Screening and Health Behaviors
RCT ID
AEARCTR-0017283
Initial registration date
November 19, 2025

Initial registration date is when the trial was registered.

It corresponds to when the registration was submitted to the Registry to be reviewed for publication.

First published
November 25, 2025, 7:44 AM EST

First published corresponds to when the trial was first made public on the Registry after being reviewed.

Locations

Region

Primary Investigator

Affiliation
Johns Hopkins

Other Primary Investigator(s)

Additional Trial Information

Status
Completed
Start date
2025-11-20
End date
2025-11-21
Secondary IDs
Prior work
This trial does not extend or rely on any prior RCTs.
Abstract
Our paper models the decision to seek low-dose CT (LDCT) lung cancer screening. Because 80$\%$ of lung cancers are caused by cigarette smoking, we build a dynamic structural model in which screening and smoking are chosen simultaneously. Screening has the potential to identify early-stage lung cancer, when it is potentially treatable, and it alleviates uncertainty about the true lung cancer state. At the same time, screening is costly in both pecuniary and non-pecuniary terms, and it is not perfect in the sense that false positives may lead to unnecessary care. Smoking generates utility, particularly for those with significant and recent smoking histories, but it also increases the risk for both lung cancer and other chronic conditions. Our goal is to estimate the model and to simulate policy counterfactual scenarios that address both costs and benefits of screening.

To directly estimate the model, we would need longitudinal information on screening and smoking behaviors, subjective beliefs, screening outcomes, and health transitions over many years. Because such data do not exist, our empirical approach combines data from several sources. For our primary data source, we plan to conduct a randomized information experiment that will evaluate how brief, randomized information about stigma, perceived quality, and price affect intentions to seek low-dose CT (LDCT) lung cancer screening within 12 months. Our population of interest are those above the age of 40 who have some cigarette smoking history. Before the information treatments, we will assess eligibility for $0 out-of-pocket (OOP) screening based on USPSTF 2022 guidelines. We intend to report the average treatment effects generated by our experiment and the heterogeneity in these effects by theoretically relevant factors at baseline, including stigma, perceptions of quality, and income. We will then use these treatment effects to calibrate our model. We will run our survey on Prolific.
External Link(s)

Registration Citation

Citation
Darden, Michael. 2025. "Endogenous Screening and Health Behaviors." AEA RCT Registry. November 25. https://doi.org/10.1257/rct.17283-1.0
Experimental Details

Interventions

Intervention(s)
We intend to run a survey on the Prolific platform. We restrict attention to those over the age of 40 with some smoking history. The survey captures risk and time preferences and basic SES measures. We also assess beliefs and expectations regarding lung cancer and lung cancer screening. Then, we randomize respondents into one of four arms: control, stigma, quality, and price. We ask respondents about their likelihood of seeking lung cancer screening in the next 12 months, and we frame the question differently across arms. The control arm presents a neutral framing; the stigma arm reassures respondents that clinicians will not be judgmental during the screening; the quality arm informs respondents of the true false positive rate in LDCT screening; and the price arm presents out-of-pocket cost information depending on whether the respondent satisfies USPSTF eligibility for free screening. For those eligible (as assessed by the survey), price arm respondents are informed of their eligibility; for those ineligible, we randomized an out-of-pocket price for screening. We assess intention to screen on a 0-100 scale as well as with a binary decision. Following the intention to screen questions, we assess comprehension. Finally, we assess intention to smoke cigarettes over the next 12 months. Half of respondents are randomized to a neutral framing of the smoking question, and half of respondents are randomized to a framing that suggests a recent "clean" screening.
Intervention (Hidden)
We intend to run a survey on the Prolific platform. We restrict attention to those over the age of 40 with some smoking history. The survey captures risk and time preferences and basic SES measures. We also assess beliefs and expectations regarding lung cancer and lung cancer screening. Then, we randomize respondents into one of four arms: control, stigma, quality, and price. We ask respondents about their likelihood of seeking lung cancer screening in the next 12 months, and we frame the question differently across arms. The control arm presents a neutral framing; the stigma arm reassures respondents that clinicians will not be judgmental during the screening; the quality arm informs respondents of the true false positive rate in LDCT screening; and the price arm presents out-of-pocket cost information depending on whether the respondent satisfies USPSTF eligibility for free screening. For those eligible (as assessed by the survey), price arm respondents are informed of their eligibility; for those ineligible, we randomized an out-of-pocket price for screening. We assess intention to screen on a 0-100 scale as well as with a binary decision. Following the intention to screen questions, we assess comprehension. Finally, we assess intention to smoke cigarettes over the next 12 months. Half of respondents are randomized to a neutral framing of the smoking question, and half of respondents are randomized to a framing that suggests a recent "clean" screening.
Intervention Start Date
2025-11-20
Intervention End Date
2025-11-21

Primary Outcomes

Primary Outcomes (end points)
Intent to seek LDCT lung cancer screening; intent to smoke cigarettes.
Primary Outcomes (explanation)

Secondary Outcomes

Secondary Outcomes (end points)
Secondary Outcomes (explanation)

Experimental Design

Experimental Design
We intend to run a survey on the Prolific platform. We restrict attention to those over the age of 40 with some smoking history. The survey captures risk and time preferences and basic SES measures. We also assess beliefs and expectations regarding lung cancer and lung cancer screening. Then, we randomize respondents into one of four arms: control, stigma, quality, and price. We ask respondents about their likelihood of seeking lung cancer screening in the next 12 months, and we frame the question differently across arms. The control arm presents a neutral framing; the stigma arm reassures respondents that clinicians will not be judgmental during the screening; the quality arm informs respondents of the true false positive rate in LDCT screening; and the price arm presents out-of-pocket cost information depending on whether the respondent satisfies USPSTF eligibility for free screening. For those eligible (as assessed by the survey), price arm respondents are informed of their eligibility; for those ineligible, we randomized an out-of-pocket price for screening. We assess intention to screen on a 0-100 scale as well as with a binary decision. Following the intention to screen questions, we assess comprehension. Finally, we assess intention to smoke cigarettes over the next 12 months. Half of respondents are randomized to a neutral framing of the smoking question, and half of respondents are randomized to a framing that suggests a recent "clean" screening.
Experimental Design Details
Randomization Method
The survey is built in Qualtrics. Qualtrics does the simple randomization.
Randomization Unit
Individual.
Was the treatment clustered?
No

Experiment Characteristics

Sample size: planned number of clusters
4,000 Individuals.
Sample size: planned number of observations
4,000 Individuals.
Sample size (or number of clusters) by treatment arms
Intention to Screen: 1,000 per arm * 4 arms = 4,000
Intention to Smoke: 2,000 per arm * 2 arms = 4,000

The two randomized questions are independent.
Minimum detectable effect size for main outcomes (accounting for sample design and clustering)
Our intention is to field the survey to 4,000 respondents, with 25% in each of the four arms. If we assume that 35% of our sample will be USPSTF eligible, that our rich set of baseline characteristics explain 20% of the variation in intention to screen, and that the standard deviation of intention to screen is 25, then the minimum detectable effect for each of our treatment arms is 2.29 percentage points when alpha of 0.05 and the power is set of 0.8.
IRB

Institutional Review Boards (IRBs)

IRB Name
Johns Hopkins Homewood IRB
IRB Approval Date
2025-11-17
IRB Approval Number
AM00022589
Analysis Plan

Analysis Plan Documents

Pre-Analysis Plan

MD5: 23f0bc393a5755a37d57d7de939f921e

SHA1: 29764db7e1505c8b6af060897499f82ae0f643c1

Uploaded At: November 19, 2025

Survey Instrument

MD5: 0ed2a2c40c27f112c2fd1c321af7f3c3

SHA1: ac176ed058bea4ad27083c74e9ab1071f3ac9875

Uploaded At: November 19, 2025

Post-Trial

Post Trial Information

Study Withdrawal

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Intervention

Is the intervention completed?
No
Data Collection Complete
Data Publication

Data Publication

Is public data available?
No

Program Files

Program Files
Reports, Papers & Other Materials

Relevant Paper(s)

Reports & Other Materials