Default Option Nudging Intervention to Improve the Adherence Rates of Cancer Screening

Default Option Nudging Intervention to Improve the Adherence Rates of Cancer Screening in High-risk Population: Randomized Controlled Trial and Intervention Disclosure Analysis

The goal of this clinical trial is to learn if a behavioral "nudge" strategy, specifically a default option, can improve screening participation in populations at high risk for lung and stomach cancer. The main questions it aims to answer are:

1. Does presenting a screening appointment as a default option increase the likelihood that high-risk individuals will choose to be screened?
2. How do participants react, and what is their level of acceptance, when the nudge intervention is disclosed to them?
3. Does this transparency (disclosing the nudge) change their subsequent screening decisions? Researchers will compare a default option group to a standard control group to see if the nudge effectively increases screening adherence.

Participants will:

1. Read a short educational text about lung or stomach cancer and its screening.
2. Complete an online questionnaire.
3. Make a decision regarding a simulated cancer screening appointment.
4. Read a disclosure explaining the behavioral nudge strategy used during the study.
5. Re-evaluate their screening decision and answer questions regarding their attitude toward the nudge.

Study Overview

• Status: Completed
• Conditions: Stomach Neoplasms; Lung Neoplasms; Patient Compliance; Early Detection of Cancer
• Intervention / Treatment: Behavioral: Default Options

• Study Type: Interventional
• Enrollment (Actual): 1200
• Phase: Not Applicable

Contacts and Locations

Study Locations

• China
  • Heilongjiang
    • Harbin, Heilongjiang, China, 150081
      • Harbin Medical University

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: Yes

Description

Inclusion Criteria:

• High-risk population of lung cancer or gastric cancer.
• Lung cancer high-risk definition (based on the 2024 Lung Cancer Screening and Early Diagnosis and Treatment Program organized by the National Health Commission of the PRC): Age ≥50 years and pack-years of smoking ≥20, including former smoking ≥20 pack-years, but smoking cessation less than 15 years (Note: Pack-years of smoking = number of packs smoked per day × number of years smoked).
• Gastric cancer high-risk definition (based on the 2024 Gastric Cancer Screening and Early Diagnosis and Treatment Program organized by the National Health Commission of the PRC): Age ≥45 years old and living in areas with a high incidence of gastric cancer (Liaoning, Fujian, Gansu, Shandong, Jiangsu).
• Ability to read and comprehend simplified Chinese.
• The informed consent statement was read and confirmed.

Exclusion Criteria:

• Reading impairment preventing independent questionnaire completion.
• Failure to pass attention checks and logical consistency tests embedded within the questionnaire.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Health Services Research
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: Double

Number of Arms

4

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
No Intervention: control group (lung cancer screening); Control group participants received neutral, informational content about lung cancer and screening. This content included lung cancer's status as a leading cause of cancer mortality, the challenges of late-stage diagnosis, and LDCT as the gold standard screening method. Participants were informed that high-risk individuals, particularly long-term smokers, require annual screening due to elevated cancer risk, with each participant explicitly told they qualified as high-risk due to their smoking history. Meanwhile, CanSPUC and its purpose were also shown to the participants. The screening participation question for controls was framed as: "We provide available time slots for free lung cancer screening. You can directly view available appointment times and make reservations according to your preference. Would you like to schedule lung cancer screening?"
Experimental: intervention group (lung cancer screening); Intervention participants received the same neutral information plus a default option nudge. The critical modification involved reframing the screening participation measure as: "We have already scheduled a free lung cancer screening appointment for you, which you can attend at your convenience. If you do not wish to participate, please indicate below." We also default to "Yes, I would like to make an appointment for lung cancer screening and see the available hours for lung cancer screening" for this question.	Behavioral: Default Options; Participants in this arm are subjected to a behavioral "nudge" using a default option mechanism during a simulated online appointment process for cancer screening. Instead of being asked to actively schedule an appointment (an opt-in approach), the screening appointment is presented to them as pre-selected or pre-scheduled (an opt-out approach). Furthermore, to evaluate the ethical and behavioral impact of transparency, this intervention uniquely includes a "disclosure" phase: after the initial decision, participants are explicitly informed about the nudge strategy that was just applied to them, and their screening intention is immediately re-measured.
No Intervention: control group (gastric cancer screening); Control group participants received neutral, informational content about gastric cancer and screening. This content included gastric cancer's status as a cause of cancer mortality, the challenges of late-stage diagnosis, and endoscope as the gold standard screening method. Participants were informed that high-risk individuals require screening per 5 years, with each participant explicitly told they qualified as high-risk due to their living regions. Meanwhile, CanSPUC and its purpose were also shown to the participants. The screening participation question for controls was framed as: "We provide available time slots for free gastric cancer screening. You can directly view available appointment times and make reservations according to your preference. Would you like to schedule gastric cancer screening?"
Experimental: intervention group (gastric cancer screening); Intervention participants received the same neutral information plus a default option nudge. The critical modification involved reframing the screening participation measure as: "We have already scheduled a free gastric cancer screening appointment for you, which you can attend at your convenience. If you do not wish to participate, please indicate below." We also default to "Yes, I would like to make an appointment for gastric cancer screening and see the available hours for lung cancer screening" for this question.	Behavioral: Default Options; Participants in this arm are subjected to a behavioral "nudge" using a default option mechanism during a simulated online appointment process for cancer screening. Instead of being asked to actively schedule an appointment (an opt-in approach), the screening appointment is presented to them as pre-selected or pre-scheduled (an opt-out approach). Furthermore, to evaluate the ethical and behavioral impact of transparency, this intervention uniquely includes a "disclosure" phase: after the initial decision, participants are explicitly informed about the nudge strategy that was just applied to them, and their screening intention is immediately re-measured.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Percentage of Participants Who Accept the Cancer Screening Appointment	This outcome is assessed via a dichotomous choice (Yes/No) embedded in the simulated online scheduling system within the questionnaire. The value reported will be the percentage of participants who choose to accept and schedule the screening appointment.	Immediately after the default option intervention

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Participant Attitude Score Towards the Default Option Nudge	This measure is assessed via a self-reported questionnaire using a Likert scale. Scores range from 1 to 5, where 1 indicates a very negative attitude and 5 indicates a very positive attitude. Higher scores represent a better attitude towards the nudge strategy.	Immediately after the disclosure of the intervention
Self-Reported Score of the Nudge's Influence on Decision-Making	This measure is assessed via a self-reported questionnaire using a Likert scale. Scores range from 1 to 5, where 1 indicates no influence and 5 indicates extreme influence. Higher scores indicate that the participant felt the default option had a greater influence on their appointment decision.	Immediately after the disclosure of the intervention
Acceptance Score of the Default Option Nudge in Public Health Services	This measure is assessed via a self-reported questionnaire using a Likert scale. Scores range from 1 to 5, where 1 indicates completely unacceptable and 5 indicates completely acceptable. Higher scores indicate higher social acceptance and suitability of using such behavioral nudges in public health promotion.	Immediately after the disclosure of the intervention
Percentage of Participants Who Accept the Appointment After Disclosure	This outcome is assessed via a secondary dichotomous choice (Yes/No) presented after the participant reads the disclosure statement explaining the nudge. The value reported is the percentage of participants who choose to accept the screening at this final stage.	Immediately after the disclosure of the intervention

Collaborators and Investigators

• Sponsor: Harbin Medical University

Study record dates

Study Major Dates

• Study Start (Actual): April 27, 2025
• Primary Completion (Actual): June 1, 2025
• Study Completion (Actual): June 1, 2025

Study Registration Dates

• First Submitted: June 23, 2026
• First Submitted That Met QC Criteria: June 26, 2026
• First Posted (Actual): July 2, 2026

Study Record Updates

• Last Update Posted (Actual): July 2, 2026
• Last Update Submitted That Met QC Criteria: June 26, 2026
• Last Verified: June 1, 2026

More Information

Terms related to this study

• Keywords: Cancer Screening; Behavioral Economics; Nudge; Default Option; Screening Adherence; Disclosure Effect
• Additional Relevant MeSH Terms: Neoplasms by Site; Neoplasms; Respiratory Tract Diseases; Gastrointestinal Neoplasms; Digestive System Neoplasms; Digestive System Diseases; Gastrointestinal Diseases; Stomach Diseases; Lung Diseases; Respiratory Tract Neoplasms; Thoracic Neoplasms; Behavior; Treatment Adherence and Compliance; Health Behavior; Patient Acceptance of Health Care; Stomach Neoplasms; Lung Neoplasms; Patient Compliance
• Other Study ID Numbers: HMUIRB2025029PRE

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: YES
• IPD Plan Description: All collected de-identified individual participant data (IPD) that underlie the results reported in the final publication. This includes demographic characteristics, group allocation, behavioral screening decisions, and responses related to attitudes toward the disclosure intervention.
• IPD Sharing Time Frame: Data will be available beginning 6 months and ending 36 months following the publication of the article.
• IPD Sharing Access Criteria: Researchers who provide a methodologically sound proposal.
• IPD Sharing Supporting Information Type: STUDY_PROTOCOL; SAP; ICF

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No