Investigators developed an online educational module (ESTIMATE) to teach Gastroenterology (GI) trainees how to estimate polyp size using a snare. Key components include video instruction and real-time feedback incorporated over a 40-item polyp size assessment test. Trainees from GI fellowship programs will be randomized to one of four groups: control (no video, no feedback), video-only, feedback-only, and video + feedback. Participants will classify polyps into one of three size categories:- diminutive (1-5 mm), small (6-9 mm), and large (≥10 mm). Primary outcome is accuracy of polyp size classification [diminutive (1-5 mm), small (6-9 mm), and large (≥10 mm)]. Secondary outcomes include accuracy of exact polyp size (in mm), cumulative accuracy (to plot learning curves), confidence level of polyp size classification, and directionality of inaccuracy (polyp size overestimation vs underestimation).

Study Design This is a prospective, multicenter educational randomized controlled trial. Trainees from five Accreditation Council for Graduate Medical Education (ACGME)-accredited GI fellowship training programs in the US will be invited to participate.

Study Materials (ESTIMATE Online Educational Module) The Estimating Polyp Size with Snare Tool to Improve Measurement Accuracy for Trainee Education (ESTIMATE) online educational module was developed by the study team over an 11-month development phase from September 2020 - August 2021. ESTIMATE is a user-friendly, interactive, web-based teaching module consisting of two main educational components: (1) video instruction and (2) real-time feedback during a polyp size assessment test. Video instruction is provided in a five-minute didactic clip that narrates the importance of accurate polyp size classification and demonstrates proper technique for positioning the snare to estimate polyp size. Examples of both correct and incorrect technique are provided. Several case examples, with opportunity for trainee interaction and response, are also included.

The polyp size assessment test includes 40 polyp sizing questions. Each question contains a still image of a polyp with an adjacent snare and asks participants to correctly identify the polyp's size into one of the following clinically relevant size categories: diminutive (1-5 mm), small (6-9 mm), and large (≥10 mm), as well as the exact polyp size in mm. Participants are also asked to provide their confidence level (high or low) with each response. High confidence is defined as a sufficient level of certainty in polyp size to commit to a surveillance interval recommendation based on the response. Low confidence is defined as an insufficient level of certainty in polyp size to commit to a surveillance interval recommendation based on the response.

Real-time feedback on correct polyp size is provided immediately after a response is submitted in the form of a series of images with overlying graphics that demonstrate polyp size relative to the adjacent snare with a final image of the resected polyp affixed to a cork board and ruler. Investigators used measurement of the immediate post-resection, pre-formalin fixation polyp affixed to a cork board with an adjacent ruler to determine correct size. The feedback image deck will be provided in continuous fashion after each response as participants progress through the test.

Randomization In order to assess the impact of the key educational components of our module (video instruction and feedback), participants will be randomized in REDCap to one of four study groups: control, video-only, feedback-only, or video + feedback. The control group will complete the 40-item polyp size assessment test without receiving any video instruction or feedback. The video-only group will watch the video instructional clip and then completed the assessment, but will not receive any feedback after each question. The feedback-only group will receive feedback after each question, but will not watch the video. Lastly, the video + feedback group will receive both video instruction and feedback as they complete the assessment.

Data Collection and Reporting System All data will be collected and managed using Research Electronic Data capture (REDCap).

Statistical Analysis & Sample Size Considerations Bivariable analyses will be performed to identify potential differences between groups. Binomial regressions will be conducted to detect differences between the control and intervention groups in accuracy of polyp size by size classification and exact size in mm. Generalized linear mixed models will be used to assess differences in confidence while accounting for multiple responses within each participant. Models will be evaluated using a type I error rate of 0.05. Analyses will be conducted using R version 4.1.1. In order to achieve 80% power to detect a 20% difference between the three intervention groups and the control group, we will need to enroll twelve trainees within each group (48 total).

Inclusion Criteria:

• GI trainees who have never received formal training in, nor had participated in a research study on, polyp sizing
• Informed consent

Exclusion Criteria:

• Those who do not complete the educational module during the allotted time

The investigators will be blinded regarding which participants are randomized to which arm.