Effectiveness Of Nudges Research Articles

Protocol for a pragmatic stepped wedge cluster randomized clinical trial testing behavioral economic implementation strategies to increase supplemental breast MRI screening among patients with extremely dense breasts

BackgroundIncreased breast density augments breast cancer risk and reduces mammography sensitivity. Supplemental breast MRI screening can significantly increase cancer detection among women with dense breasts. However, few women undergo this exam, and screening is consistently lower among racially minoritized populations. Implementation strategies informed by behavioral economics (“nudges”) can promote evidence-based practices by improving clinician decision-making under conditions of uncertainty. Nudges directed toward clinicians and patients may facilitate the implementation of supplemental breast MRI.MethodsApproximately 1600 patients identified as having extremely dense breasts after non-actionable mammograms, along with about 1100 clinicians involved with their care at 32 primary care or OB/GYN clinics across a racially diverse academically based health system, will be enrolled. A 2 × 2 randomized pragmatic trial will test nudges to patients, clinicians, both, or neither to promote supplemental breast MRI screening. Before implementation, rapid cycle approaches informed by clinician and patient experiences and behavioral economics and health equity frameworks guided nudge design. Clinicians will be clustered into clinic groups based on existing administrative departments and care patterns, and these clinic groups will be randomized to have the nudge activated at different times per a stepped wedge design. Clinicians will receive nudges integrated into the routine mammographic report or sent through electronic health record (EHR) in-basket messaging once their clinic group (i.e., wedge) is randomized to receive the intervention. Independently, patients will be randomized to receive text message nudges or not. The primary outcome will be defined as ordering or scheduling supplemental breast MRI. Secondary outcomes include MRI completion, cancer detection rates, and false-positive rates. Patient sociodemographic information and clinic-level variables will be examined as moderators of nudge effectiveness. Qualitative interviews conducted at the trial’s conclusion will examine barriers and facilitators to implementation.DiscussionThis study will add to the growing literature on the effectiveness of behavioral economics-informed implementation strategies to promote evidence-based interventions. The design will facilitate testing the relative effects of nudges to patients and clinicians and the effects of moderators of nudge effectiveness, including key indicators of health disparities. The results may inform the introduction of low-cost, scalable implementation strategies to promote early breast cancer detection.Trial registrationClinicalTrials.gov NCT05787249. Registered on March 28, 2023.

Optimal nudging for cognitively bounded agents: A framework for modeling, predicting, and controlling the effects of choice architectures.

People's decisions often deviate from classical notions of rationality, incurring costs to themselves and society. One way to reduce the costs of poor decisions is to redesign the decision problems people face to encourage better choices. While often subtle, these nudges can have dramatic effects on behavior and are increasingly popular in public policy, health care, and marketing. Although nudges are often designed with psychological theories in mind, they are typically not formalized in computational terms and their effects can be hard to predict. As a result, designing nudges can be difficult and time-consuming. To address this challenge, we propose a computational framework for understanding and predicting the effects of nudges. Our approach builds on recent work modeling human decision making as adaptive use of limited cognitive resources, an approach called resource-rational analysis. In our framework, nudges change the metalevel problem the agent faces-that is, the problem of how to make a decision. This changes the optimal sequence of cognitive operations an agent should execute, which in turn influences their behavior. We show that models based on this framework can account for known effects of nudges based on default options, suggested alternatives, and information highlighting. In each case, we validate the model's predictions in an experimental process-tracing paradigm. We then show how the framework can be used to automatically construct optimal nudges, and demonstrate that these nudges improve people's decisions more than intuitive heuristic approaches. Overall, our results show that resource-rational analysis is a promising framework for formally characterizing and constructing nudges. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

Effect of removing an oncologist-directed behavioral nudge on sustaining rates of serious illness conversations: An interrupted time series analysis.

242 Background: Behavorial economic nudges are increasingly used in oncology settings to encourage evidence-based practices, such as serious illness conversations (SIC). Prior work demonstrated the effectiveness of an oncologist-directed nudge identifying patients at high risk of 180-day mortality, which led to a 3-fold increase in SIC documentation. It is unknown whether such nudges must continue indefinitely to sustain effective behavior change, or whether clinician behavior change would persist in their absence. The objective of this analysis was to examine the effect of removing an oncologist-directed nudge on overall SIC rates. Methods: From 2019 to 2022, clinicians within our institution received a nudge consisting of weekly performance feedback on SIC completion and opt-out text messages identifying patients at high-risk of 180-day mortality based on a validated machine-learning algorithm. In March 2022, at the conclusion of clinical trial NCT04867850, this program ended. For this analysis, the population included adult patients seen by a medical oncologist at one of 11 practices between Sept 2021 and Sept 2022. Patient encounters with an SIC documented in the previous year were excluded, as well as those occurring during a washout period (March-April 2022). SICs were attributed to an encounter if documented within 30 days. The primary outcome was the number of SICs documented per 1000 patient encounters. We used linear probability models and an interrupted time series analysis at the patient-encounter level to analyze the association between nudge cessation and SIC rates. All analyses were unadjusted. Results: 111,459 encounters were included in the final analysis (56.9% prior to nudge cessation). Demographic data showed mean age 64.16 (SD 13.29), 57.02% female, 75.25% non-Hispanic white, 61.88% Medicare. There were 1,517 unique encounters with an SIC documented within 30 days (1.36%), with 1,030 pre-cessation (1.62%) and 487 post-cessation (1.01%). Rates of SICs were 15.3 per 1000 encounters in February 2022 (pre-cessation) vs. 9.7 in May 2022 (post-cessation), representing a 37% decline (Table). Unadjusted interrupted time series analyses showed a significant decrease in documented SICs per 1000 encounters (odds ratio 0.64, 95% CI 0.57 - 0.71). Conclusions: Removal of a clinician nudge was associated with a significant decline in SIC rates, suggesting a lack of sustained clinician behavior change without an ongoing behavioral nudge. Because nudges may be required indefinitely to promote evidence-based practices such as SICs, their design should be minimally intrusive and easily adaptable to evolving care standards. Adjusted analyses, marginal effects analysis, and time-to-event analyses are in progress.[Table: see text]

“Feel free to ask”: Nudging to promote asking questions in the online classroom

Asking questions is vital for learning, yet students seldom exhibit this behavior. Given the increasing presence of online classrooms in tertiary education, it is much needed to examine ways to encourage students to ask questions and increase their engagement. Despite the critical role of asking questions to enhance learning, little is known in research on promoting this behavior. Therefore, in this paper, we empirically tested the effect of nudging – a novel approach in education consisting of subtle interventions to change behavior – in online classrooms in tertiary education on question asking behavior, student engagement, and grades. In Experiment 1 (n = 1011), the teacher's virtual background prompted questions (prompt nudge), while in Experiment 2 (n = 449), the teacher set a goal for the students to ask one question per session (goal-setting nudge). We found a trend towards a positive effect of the prompt nudge on questions, but not on grades. Exploratory analyses revealed this was driven by students who already asked many questions. We found no effect of the goal-setting nudge on any measure, nor any effect in either experiment on student engagement. The findings demonstrate that the prompt nudge can be a possible useful and easy to implement tool to encourage questions in the online classroom.

The Nutri-Score – A Quantitative Study of the Effectiveness of Visual Nudging on Consumer Behavior

Globally, unhealthy diets have a significant impact on people's risk of disease and mortality, so the German Ministry of Nutrition and Agriculture also focuses on healthier and balanced diets in its reduction and innovation strategy. By means of the Nutri-Score, the nudging principle is used to provide consumers with additional nutritional labelling and to encourage the purchase of healthier foods. The aim of this study is to investigate the effectiveness of visual nudging in FMCGs, i.e., the food industry, in the form of the Nutri-Score on consumers' purchase decisions and to validate its robustness with respect to demographic factors. For this purpose, an online survey was conducted with 294 participants leading to a total number of up to 3,528 observations regarding their purchase intention of selected products. A logistic regression analysis showed that the purchasing behaviour changed with the insertion of the Nutri-Score per se and with subjects avoiding negatively rated products and preferring positively rated ones. It was further shown that these effects persist regardless of participants’ demographics.

The role of attention and health goals in nudging healthy food choice.

Nudging is a promising intervention technique that supports people in pursuing their healthy eating goals. Recent research suggests that, despite previous assumptions, disclosure of the presence of a nudge does not compromise nudge effectiveness. However, it is unknown whether attention to a nudge affects nudge effects. We assessed the role of attention systematically, by examining explicit and implicit attention to nudges, while also exploring healthy eating goals as a potential moderator. Participants were assigned to a nudge (i.e., a shopping basket inlay with pictures of healthy items) or control condition (i.e., a shopping basket inlay with neutral pictures) and chose a snack in an experimental supermarket field study. Explicit and implicit attention (with a mobile eye-tracker) to nudges, healthiness of snack choice, and healthy eating goals were assessed. Results showed that attention to the nudge did not hamper the nudge's effect. Furthermore, individuals with strong healthy eating goals made healthier food choices in the nudge condition. Individuals with weak to non-existent healthy eating goals were not influenced by the nudge. Findings are in line with the viewpoint that nudging does not by definition work 'in the dark', and suggests that nudges support people in adhering to their healthy eating goal.

Investigating the impact of 'dark nudges' on drinking intentions: A between groups, randomized and online experimental study.

This study explored how 'dark nudges' (tactics used in alcohol industry-funded responsible drinking campaigns) affect drinking intentions, perceived source credibility and whether individual differences in perceptions of prototypical drinkers moderated these effects. Two 2 × 2 between-groups online experimental studies. Study 1 (N = 164) presented three alcohol health messages per condition, comprising social norm (healthy/unhealthy ("dark nudge")) by frame (loss/gain). Study 2 (N = 229) presented one message per condition, comprising cancer causality (single cause/multiple causes (dark nudge)) by funding disclosure (disclosure/non-disclosure (dark nudge)). Outcomes were drinking intentions and perceived source credibility. Exploratory analyses considered prototype perceptions as a between-subjects moderator. No significant effects of message frame, social norm, fundi or multiple cancer causality arguments on drinking intentions were found. In Study 2, in the dark nudge multiple cancer causality conditions, perceived source credibility was high when funding was undisclosed, but significantly lower when it was disclosed. Exploratory analyses suggested effects were moderated by prototype similarity. In Study 1, higher perceived similarity to a heavy drinker and lower perceived similarity to a responsible drinker were associated with higher drinking intentions in the unhealthy norm/gain frame condition, but lower drinking intentions in the other conditions. Framing, social norm, funding disclosure and multiple causality manipulations as tested in this study did not exert a dark nudge effect on drinking intentions. However, the exploratory analyses suggest it could be hypothesised that the types of messages used in alcohol industry-funded responsible drinking campaigns may result in greater drinking intentions among those who identify more as heavy drinkers and less as responsible drinkers. Perceived prototype similarity may be an important moderator of the impact of alcohol health messages that warrants further research. Study 2 suggests disclosure of industry funding guides judgements of the credibility of sources of misleading messages about alcohol and cancer.

Tackling steroid phobia: Insights from behavioural economics and psychological approaches

AbstractSteroid phobia, characterized by an irrational fear or avoidance of topical corticosteroids, poses a significant challenge to the effective treatment of various skin conditions, including atopic dermatitis (AD) and psoriasis. This issue has its roots in the introduction of topical corticosteroids in the 1950s and has been perpetuated by concerns regarding adverse effects and misinformation. International Dermatological Societies including the Japanese Dermatological Association have endeavored to address this problem by providing information and guidance to physicians and patients, resulting in a better understanding of appropriate steroid use and risk management. Despite these efforts, steroid phobia has not been fully resolved in the world, including in Japan.To shed light on potential solutions, this review explores the field of behavioral economics, which offers insights into human decision‐making processes and cognitive biases. Richard Thaler's concept of nudges emerges as a promising strategy for influencing patients' decision‐making regarding steroid treatments. However, the effectiveness of nudges may vary depending on the strength of an individual's concerns and fears. In cases where patients exhibit strong resistance to steroid use, alternative psychological techniques that establish trust and facilitate clear communication may be more beneficial.This review emphasizes the necessity of adopting a multifaceted approach that integrates principles from behavioral economics and employs complementary psychological strategies to address steroid phobia and enhance treatment adherence in affected patient populations. By combining these approaches, healthcare professionals can tackle the complex nature of steroid phobia and promote better treatment outcomes for patients with skin conditions.

Digitally nudging users to explore off-profile recommendations: here be dragons

In many application domains of recommender systems, e.g., on media streaming sites, one main goal of the provider of the recommendation service is to increase the engagement of users by helping them discover new types of content they like. Standard collaborative filtering algorithms by design often lead to a certain level of discovery. Nonetheless, in certain domains, it may be helpful to more actively promote content to users beyond their past preference profile (“off-profile”) and thereby help users explore new content. However, when showing such off-profile content to users in combination with more familiar content, the new content items may be overlooked. In this research, we explore to what extent digital nudging, i.e., subtly directing user choices in a specific direction, can help to raise the attention and interest of users for off-profile content. We conducted a user study (N=1064\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$N=1064$$\\end{document}) on a real-world social book recommendation app. We find that users who are nudged towards recommended books of their non-preferred genres significantly more often put these off-profile books on their reading lists, thus confirming the effectiveness of digital nudging in this application. However, we also found that digital nudges may negatively impact the users’ beliefs and attitudes towards the system and a more limited intention to use the system in the future. As a result, we find that digital nudging in recommendations, while effective in the short run, must be done with due care, keeping an eye on the overall quality perceptions by users and potentially harmful long-term effects.

A Mild Approach to Prebunking Health Misinformation in Social Media: Digital Nudging

ABSTRACTThe governance of health misinformation has been a hot topic in both social practice and academic research. Due to its proactive and timely nature, prebunking represents an emerging and efficacious intervention. However, previous research on prebunking primarily focuses on presenting arguments or techniques to the public in a direct and coercive manner, which remains limited in its scope and efficacy. This study aims to implement prebunking in social media by utilizing a milder approach, namely digital nudging. We conduct a web‐based pre‐experiment to test the effectiveness of warning, social and disclosure nudge, and obtain data from 104 participants. The preliminary results show that the warning and social nudge can mitigate the credibility of misinformation and decrease individual's sharing likelihood. Furthermore, eHealth literacy acts as the moderator in the impact of social nudge. This study broadens the comprehensions of the misinformation governance and digital nudging, and furnishes practical implications for the implementation of prebunking in social media.

The nudge effect to change the previous users' misbehaviors to stewardship behavior in personal mobility platforms

PurposeThis research aims to examine some nudges for creating psychological ownership in order to reduce misbehaviors, consequently encouraging subsequent users to demonstrate stewardship behaviors.Design/methodology/approachThis research examined the sentiment of tweets (Study 1) to explore user experience and conducted two experiments (Studies 2 and 3) to test the hypotheses.FindingsThe misbehavior of the previous user in relation to the subsequent user's stewardship behavior was moderated by nudges based on self-investment and local identity. Perceived responsibility mediated the relationship between misbehavior and stewardship behavior as a result of nudges.Originality/valueThe findings of this study provide a framework for the transition from misbehavior to stewardship behavior in PMVs.

Eye image effect in the context of pedestrian safety: a French questionnaire study.

Human behavior is influenced by the presence of others, which scientists also call 'the audience effect'. The use of social control to produce more cooperative behaviors may positively influence road use and safety. This study uses an online questionnaire to test how eyes images affect the behavior of pedestrians when crossing a road. Different eyes images of men, women and a child with different facial expressions -neutral, friendly and angry- were presented to participants who were asked what they would feel by looking at these images before crossing a signalized road. Participants completed a questionnaire of 20 questions about pedestrian behaviors (PBQ). The questionnaire was received by 1,447 French participants, 610 of whom answered the entire questionnaire. Seventy-one percent of participants were women, and the mean age was 35 ± 14 years. Eye images give individuals the feeling they are being observed at 33%, feared at 5% and surprised at 26%, and thus seem to indicate mixed results about avoiding crossing at the red light. The expressions shown in the eyes are also an important factor: feelings of being observed increased by about 10-15% whilst feelings of being scared or inhibited increased by about 5% as the expression changed from neutral to friendly to angry. No link was found between the results of our questionnaire and those of the Pedestrian Behavior Questionnaire (PBQ). This study shows that the use of eye images could reduce illegal crossings by pedestrians, and is thus of key interest as a practical road safety tool. However, the effect is limited and how to increase this nudge effect needs further consideration.

Digital Nudge Stacking and Backfiring: Understanding Sustainable E-Commerce Purchase Decisions

Abstract Background: The consumption of ‘fast fashion’, which is expedited by cost-effective e-commerce systems, represents one of the major factors contributing to the acceleration of climate change. An emerging approach to steer consumers in the direction of more sustainable purchase decisions is digital nudging. This paper explores digital nudging in the context of green fashion e-commerce by testing the effectiveness of two nudging strategies on the decision to choose green fashion products (GFP) over regular fashion items. Method: This study was conducted as a between-subject online experiment (n=320) with four conditions simulating an e-commerce scenario. The participants were presented with different products: one was ecologically friendly, and another was the regular option. Depending on their randomized group allocation, the participants experienced a default nudge, a social norm nudge, a combination of both strategies, or no nudge. In addition, we conducted 10 qualitative interviews to gain a deeper understanding of consumers’ decision process. Results: Our experiment failed to demonstrate statistically significant relationships between the various nudging strategies and GFP purchase decisions. However, additional explorative analyzes confirmed a backfire effect for the combination of nudging strategies. This reveals the previously overlooked influence of participants’ identification on the effectiveness of digital nudging strategies. In addition, qualitative interviews revealed individual factors that influence sustainable e-commerce purchase decisions. Conclusion: This study contributes to information systems research by explaining the differences in the effectiveness of different nudging strategies regarding high-involvement compared to low-involvement products. Moreover, it provides empirical evidence of a backfire effect resulting from a combination of digital nudging strategies (i.e., digital nudge stacking). Finally, the study underscores the leverage that individual factors have on both GFP purchase decision and the effectiveness of nudges.

Encouraging Individual Contributions to Net-Zero Organizations: Effects of Behavioral Policy Interventions and Social Norms

To contribute to a better understanding of the determinants of climate-friendly organizational behavior, we study the potential of behavioral policy interventions and social norms to foster individual contributions to organizational decarbonization initiatives. We investigate the effects of different types of behavioral policy interventions (default nudges vs. short-term boosts) in isolation and when they are combined with normative appeals to adopt climate-friendly behaviors in an organizational context. In a 2 × 2 between-subjects experiment, we find that default nudges generally induced higher individual contributions to organizational carbon compensation programs than short-term boosts. Moreover, injunctive social norm information decreased the effectiveness of both types of behavioral interventions but affected the effectiveness of short-term boosts to a stronger extent than the effectiveness of default nudges. Contributing to the nascent literature on motivating climate change mitigating behaviors in organizational contexts, we additionally explore whether factors such as personality traits, pro-social and pro-environmental beliefs, attitudes, and behaviors, and the degree of organizational identification exert an influence on the effectiveness of the interventions and provide qualitative insights into participants’ reasoning for their decisions.

Nudging Italian university students towards healthy and sustainable food choices: An online experiment

Finding strategies to motivate consumers to make food choices that could both boost sustainability and improve their health is crucial. Literature suggests that nudging could be effective in increasing the consumption of healthy and sustainable food. This research aims at determining the effects of different nudges on university students’ food choices in the context of the online pre-ordering system of the university canteens. An experimental study was conducted in Italy with 1,312 participants using a between-subject design with one control and three treatment groups, i.e., Healthy and Sustainable Logo, Dish Placement (order of which dishes are displayed on the menu), and a combination of both nudges. Our main results show that dish placement leads to a significantly increased selection of healthy and sustainable dishes. Furthermore, both placement and the combination of the two nudges could positively influence students who already have strong sustainable and healthy eating behaviors. Finally, the population’s characteristics (i.e., age, gender, being on a low-calorie diet, and living with parents), consumers’ intention to consume healthy and sustainable food, and their eating habits should be considered when identifying a successful nudging strategy.

Informational value of visual nudges during crises: Improving public health outcomes through social media engagement amid COVID‐19

In this study, we conceptualize and empirically evaluate how large‐scale organizations can utilize the informational value of visual nudges on social media to promote safety among users and thus improve public health outcomes in the context of the coronovirus desease caused by the SARS‐CoV‐2 virus (COVID‐19) pandemic. We construct a unique panel dataset combining data collected from multiple public and proprietary sources. To operationalize visual nudges from user‐generated content, we engage in extensive manual classification of images collected from Instagram (IG), Twitter (TW), and Facebook (FB). To examine the relationship between visual nudging and COVID‐19 positivity, we rely on a combination of econometric and epidemiological models. We find that when institutional actors share more images containing mask‐related information on IG, their COVID‐19 positivity rates decrease by up to 25%, on average. Also, given the fragmentary evidence behind FB and TW effects, our results provide suggestive evidence of the “boundary condition” of the visual nudge effect. Finally, empirical evidence indicates the dynamic and curvilinear effect of visual nudges on positivity over time, such that the informational value of visual nudging is most prominent if communicated 3 to 5 weeks ahead of time, on average. Our results demonstrate the informational value of visual nudges communicated through pertinent social media channels, as well as their capacity to improve public health outcomes. This suggests the feasibility of institutional actors using social media engagement to promote safe behaviors. We conclude by discussing how our findings may be used to develop more effective communication strategies regarding public perceptions of mask use and other relevant safety measures.

Can a SME Understand Its Sustainable Practices?– A Case Analysis from the Combined Perspective ofNudging Theory and Sustainable Business Practicesin A Small Retailing Business in Australia

Sustainable business practices have been under a long-lasting and fierce debate about whether a business shouldpursue SDGs or make money. Several efforts have been made to answer this question, and the Nudging Theory, a newdevelopment in behavioral economics, has been introduced. However, research seldom emphasizes how to assist SMEsto fully understand the nudges and their related effectiveness to achieve SDGs, nor does it address the moral dilemmaspotentially involved. To fill this gap, the paper, by combining two theoretical models, develops a new framework tohelp SMEs comprehend their sustainable nudges in a moral and cost-effective approach so that SMEs’ potential mightbe fully stretched out. Also, a real-world case will be related to the theoretical Framework to assist with understandingwhich SMEs should place their emphasis on, coupled with descriptive and predictive analysis. The Process and theOutcomes of sustainable nudges are summarised as two crucial elements contributing to the effectiveness of suchsustainable nudges.

Effects of green nudges on consumer valuation of sustainable food: A discrete choice experiment

Sustainable nutrition is becoming increasingly relevant in society. This empirical study suggests that green nudges can encourage consumers to buy food that has an ecology or animal welfare label.This paper analyzes whether green nudges ‐ displaying nature pictures or providing information on other people’s behavior before the consumer makes a choice ‐ can promote more environmentally friendly food choices. Based on data from an online, discrete choice experiment conducted in Germany, in which randomly selected groups of participants were shown either one of the nudges (treatment groups) or no nudge (control group), the study finds that green nudges increase individuals’ willingness to pay more for products that have ecology and animal welfare labels. However, consumers in one of the treatment groups were willing to pay more for meat rather than the meat alternative, indicating that nudges can have an effect opposite from that intended. Future research should investigate the impact of these relatively cheap interventions with a representative sample and in a field setting.

Factors of effectiveness of green nudges for more eco-responsible behaviour – Systematic review and research directions

Considering the rise of green nudges, our objective is to determine the factors of their effectiveness through a systematic review, following the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) method, which analyses 28 articles and 73 pro-environmental nudges. Following a redefinition of the concept and a categorisation based on the construal-level theory of psychological distance (opposing the lever of the ‘how’ to that of the ‘why’ of choice), the effectiveness of green nudges is analysed. A relationship of dependence appears between the (in)effectiveness of nudges and (1) the levers, mechanisms and techniques mobilised; (2) the visibility of the behaviour by others; (3) the field of application; and (4) the geographical area. These analyses and the limitations of the work reviewed provide a basis to propose avenues for research. New theoretical insights and recommendations are provided in favour of more effective nudges for the adoption of ecological and responsible behaviours.

Using Nudges to Reduce Missed Appointments in Primary Care and Mental Health: a Pragmatic Trial

BackgroundMissed appointments (“no-shows”) are a persistent and costly problem in healthcare. Appointment reminders are widely used but usually do not include messages specifically designed to nudge patients to attend appointments.ObjectiveTo determine the effect of incorporating nudges into appointment reminder letters on measures of appointment attendance.DesignCluster randomized controlled pragmatic trial.PatientsThere were 27,540 patients with 49,598 primary care appointments, and 9420 patients with 38,945 mental health appointments, between October 15, 2020, and October 14, 2021, at one VA medical center and its satellite clinics that were eligible for analysis.InterventionsPrimary care (n = 231) and mental health (n = 215) providers were randomized to one of five study arms (four nudge arms and usual care as a control) using equal allocation. The nudge arms included varying combinations of brief messages developed with veteran input and based on concepts in behavioral science, including social norms, specific behavioral instructions, and consequences of missing appointments.Main MeasuresPrimary and secondary outcomes were missed appointments and canceled appointments, respectively.Statistical AnalysisResults are based on logistic regression models adjusting for demographic and clinical characteristics, and clustering for clinics and patients.Key ResultsMissed appointment rates in study arms ranged from 10.5 to 12.1% in primary care clinics and 18.0 to 21.9% in mental health clinics. There was no effect of nudges on missed appointment rate in primary care (OR = 1.14, 95%CI = 0.96–1.36, p = 0.15) or mental health (OR = 1.20, 95%CI = 0.90–1.60, p = 0.21) clinics, when comparing the nudge arms to the control arm. When comparing individual nudge arms, no differences in missed appointment rates nor cancellation rates were observed.ConclusionsAppointment reminder letters incorporating brief behavioral nudges were ineffective in improving appointment attendance in VA primary care or mental health clinics. More complex or intensive interventions may be necessary to significantly reduce missed appointments below their current rates.Trial NumberClinicalTrials.gov, Trial number NCT03850431.