Introduction

Colorectal cancer (CRC) is a major cause of cancer-related morbidity and mortality in the United States. Although various interventions have improved screening rates, they often require abundant resources and can be difficult to implement. Social psychology and behavioral economics principles offer an opportunity for low-cost and easy-to-implement strategies but are less common in clinical settings.

Methods

We randomized 2,000 patients aged 50-75 years eligible for CRC screening to one of the 2 mailed interventions: a previously used text-based letter describing and offering fecal immunochemical testing (FIT) and colonoscopy (usual care arm); or a letter leveraging social psychology and behavioral economics principles (e.g., implied scarcity and choice architecture), minimal text, and multiple images to offer FIT and colonoscopy (intervention arm). We compared total screening uptake, FIT uptake, and colonoscopy uptake at 1-month intervals in each group.

Results

There were 1,882 patients included in the final analysis. The mean age was 69.3 years, and baseline characteristics in the 2 groups were similar. Screening completion at 26 weeks was 19.5% in the usual care arm (16.3% FIT vs 3.2% colonoscopy, P < 0.01) and 24.1% in the intervention arm (22.1% FIT vs 2.0% colonoscopy, P < 0.01) (P = 0.02).

Discussion

Among primary care patients aged 50-75 years in an academic setting, mailed CRC outreach employing social psychology and behavioral economics principles led to a higher participation in CRC screening than usual care mailed outreach.

Translational impact

Mailed interventions to increase CRC screening should incorporate social psychology and behavioral economics principles to improve participation.

Enhancing vaccine uptake is a critical public health challenge¹. Overcoming vaccine hesitancy^2,3 and failure to follow through on vaccination intentions³ requires effective communication strategies^3,4. Here we present two sequential randomized controlled trials to test the effect of behavioural interventions on the uptake of COVID-19 vaccines. We designed text-based reminders that make vaccination salient and easy, and delivered them to participants drawn from a healthcare system one day (first randomized controlled trial) (n = 93,354 participants; clinicaltrials number NCT04800965) and eight days (second randomized controlled trial) (n = 67,092 individuals; clinicaltrials number NCT04801524) after they received a notification of vaccine eligibility. The first reminder boosted appointment and vaccination rates within the healthcare system by 6.07 (84%) and 3.57 (26%) percentage points, respectively; the second reminder increased those outcomes by 1.65 and 1.06 percentage points, respectively. The first reminder had a greater effect when it was designed to make participants feel ownership of the vaccine dose. However, we found no evidence that combining the first reminder with a video-based information intervention designed to address vaccine hesitancy heightened its effect. We performed online studies (n = 3,181 participants) to examine vaccination intentions, which revealed patterns that diverged from those of the first randomized controlled trial; this underscores the importance of pilot-testing interventions in the field. Our findings inform the design of behavioural nudges for promoting health decisions⁵, and highlight the value of making vaccination easy and inducing feelings of ownership over vaccines.