Megastudies improve the impact of applied behavioural science.

Policy-makers are increasingly turning to behavioural science for insights about how to improve citizens' decisions and outcomes1. Typically, different scientists test different intervention ideas in different samples using different outcomes over different time intervals2. The lack of comparability of such individual investigations limits their potential to inform policy. Here, to address this limitation and accelerate the pace of discovery, we introduce the megastudy-a massive field experiment in which the effects of many different interventions are compared in the same population on the same objectively measured outcome for the same duration. In a megastudy targeting physical exercise among 61,293 members of an American fitness chain, 30 scientists from 15 different US universities worked in small independent teams to design a total of 54 different four-week digital programmes (or interventions) encouraging exercise. We show that 45% of these interventions significantly increased weekly gym visits by 9% to 27%; the top-performing intervention offered microrewards for returning to the gym after a missed workout. Only 8% of interventions induced behaviour change that was significant and measurable after the four-week intervention. Conditioning on the 45% of interventions that increased exercise during the intervention, we detected carry-over effects that were proportionally similar to those measured in previous research3-6. Forecasts by impartial judges failed to predict which interventions would be most effective, underscoring the value of testing many ideas at once and, therefore, the potential for megastudies to improve the evidentiary value of behavioural science.

A megastudy of text-based nudges encouraging patients to get vaccinated at an upcoming doctor's appointment.

Many Americans fail to get life-saving vaccines each year, and the availability of a vaccine for COVID-19 makes the challenge of encouraging vaccination more urgent than ever. We present a large field experiment (N = 47,306) testing 19 nudges delivered to patients via text message and designed to boost adoption of the influenza vaccine. Our findings suggest that text messages sent prior to a primary care visit can boost vaccination rates by an average of 5%. Overall, interventions performed better when they were 1) framed as reminders to get flu shots that were already reserved for the patient and 2) congruent with the sort of communications patients expected to receive from their healthcare provider (i.e., not surprising, casual, or interactive). The best-performing intervention in our study reminded patients twice to get their flu shot at their upcoming doctor's appointment and indicated it was reserved for them. This successful script could be used as a template for campaigns to encourage the adoption of life-saving vaccines, including against COVID-19.

Which Early Withdrawal Penalty Attracts the Most Deposits to a Commitment Savings Account?

Previous research has shown that some people voluntarily use commitment contracts that restrict their own choice sets. We study how people divide money between two accounts: a liquid account that permits unrestricted withdrawals and a commitment account that is randomly assigned in a between-subject design to have either a 10% early withdrawal penalty, or a 20% early withdrawal penalty, or not to allow early withdrawals at all (i.e., an infinite penalty). When the liquid account and the commitment account pay the same interest rate, higher early-withdrawal penalties attract more commitment account deposits. This pattern is predicted by the hypothesis that some participants are partially- or fully-sophisticated present-biased agents. Such agents perceive that higher penalties generate greater scope for commitment by disincentivizing (penalized) early withdrawals. The experiment also shows that when the commitment account pays a higher interest rate than the liquid account, the positive empirical slope relating penalties and commitment deposits is flattened, suggesting that naïve present-biased agents or agents with standard exponential discounting are also in our sample. Across all of our experimental treatments, higher early withdrawal penalties on the commitment account sometimes increase and never reduce allocations to the commitment account.

Should Governments Invest More in Nudging?

Governments are increasingly adopting behavioral science techniques for changing individual behavior in pursuit of policy objectives. The types of "nudge" interventions that governments are now adopting alter people's decisions without coercion or significant changes to economic incentives. We calculated ratios of impact to cost for nudge interventions and for traditional policy tools, such as tax incentives and other financial inducements, and we found that nudge interventions often compare favorably with traditional interventions. We conclude that nudging is a valuable approach that should be used more often in conjunction with traditional policies, but more calculations are needed to determine the relative effectiveness of nudging.

Does front-loading taxation increase savings? Evidence from Roth 401(k) introductions.

Can governments increase private savings by taxing savings up front instead of in retirement? Roth 401(k) contributions are not tax-deductible in the contribution year, but withdrawals in retirement are untaxed. The more common before-tax 401(k) contribution is tax-deductible in the contribution year, but both principal and investment earnings are taxed upon withdrawal. Using administrative data from eleven companies that added a Roth contribution option to their existing 401(k) plan between 2006 and 2010, we find no evidence that total 401(k) contribution rates differ between employees hired before versus after Roth introduction, which implies that take-home pay declines and the amount of retirement consumption being purchased by 401(k) contributions increases after Roth introduction. We reject several neoclassical explanations for our null finding. Results from a survey experiment suggest two behavioral explanations: (1) employee confusion about and neglect of the tax properties of Roth balances and (2) partition dependence.

Vaccination Rates are Associated With Functional Proximity But Not Base Proximity of Vaccination Clinics.

BACKGROUND: Routine annual influenza vaccinations are recommended for persons 6 months of age and older, but less than half of US adults get vaccinated. Many employers offer employees free influenza vaccinations at workplace clinics, but even then take-up is low. OBJECTIVE: To determine whether employees are significantly more likely to get vaccinated if they have a higher probability of walking by the clinic for reasons other than vaccination. METHOD: We obtained data from an employer with a free workplace influenza vaccination clinic. Using each employee's building entry/exit swipe card data, we test whether functional proximity-the likelihood that the employee walks by the clinic for reasons other than vaccination-predicts whether the employee gets vaccinated at the clinic. We also test whether base proximity-the inverse of walking distance from the employee's desk to the clinic-predicts vaccination probability. PARTICIPANTS: A total of 1801 employees of a health benefits administrator that held a free workplace influenza vaccination clinic. RESULTS: A 2 SD increase in functional proximity is associated with a 6.4 percentage point increase in the probability of vaccination (total vaccination rate at company=40%), even though the average employee's desk is only 166 meters from the clinic. Base proximity does not predict vaccination probability. CONCLUSIONS AND RELEVANCE: Minor changes in the environment can have substantial effects on the probability of vaccination. If these results generalize, health systems should emphasize functional proximity over base proximity when locating preventive health services.

Using implementation intentions prompts to enhance influenza vaccination rates.

We evaluate the results of a field experiment designed to measure the effect of prompts to form implementation intentions on realized behavioral outcomes. The outcome of interest is influenza vaccination receipt at free on-site clinics offered by a large firm to its employees. All employees eligible for study participation received reminder mailings that listed the times and locations of the relevant vaccination clinics. Mailings to employees randomly assigned to the treatment conditions additionally included a prompt to write down either (i) the date the employee planned to be vaccinated or (ii) the date and time the employee planned to be vaccinated. Vaccination rates increased when these implementation intentions prompts were included in the mailing. The vaccination rate among control condition employees was 33.1%. Employees who received the prompt to write down just a date had a vaccination rate 1.5 percentage points higher than the control group, a difference that is not statistically significant. Employees who received the more specific prompt to write down both a date and a time had a 4.2 percentage point higher vaccination rate, a difference that is both statistically significant and of meaningful magnitude.

What Makes Annuitization More Appealing?

We conduct and analyze two large surveys of hypothetical annuitization choices. We find that allowing individuals to annuitize a fraction of their wealth increases annuitization relative to a situation where annuitization is an "all or nothing" decision. Very few respondents choose declining real payout streams over flat or increasing real payout streams of equivalent expected present value. Highlighting the effects of inflation increases demand for cost of living adjustments. Frames that highlight flexibility, control, and investment significantly reduce annuitization. A majority of respondents prefer to receive an extra "bonus" payment during one month of the year that is funded by slightly lower payments in the remaining months. Concerns about later-life income, spending flexibility, and counterparty risk are the most important self-reported motives that influence the annuitization decision.

What Goes Up Must Come Down? Experimental Evidence on Intuitive Forecasting.

Do laboratory subjects correctly perceive the dynamics of a mean-reverting time series? In our experiment, subjects receive historical data and make forecasts at different horizons. The time series process that we use features short-run momentum and long-run partial mean reversion. Half of the subjects see a version of this process in which the momentum and partial mean reversion unfold over 10 periods ('fast'), while the other subjects see a version with dynamics that unfold over 50 periods ('slow'). Typical subjects recognize most of the mean reversion of the fast process and none of the mean reversion of the slow process.

Simplification and Saving.

The daunting complexity of important financial decisions can lead to procrastination. We evaluate a low-cost intervention that substantially simplifies the retirement savings plan participation decision. Individuals received an opportunity to enroll in a retirement savings plan at a pre-selected contribution rate and asset allocation, allowing them to collapse a multidimensional problem into a binary choice between the status quo and the pre-selected alternative. The intervention increases plan enrollment rates by 10 to 20 percentage points. We find that a similar intervention can be used to increase contribution rates among employees who are already participating in a savings plan.

A Randomized Trial of Behavioral Nudges Delivered Through Text Messages to Increase Influenza Vaccination Among Patients With an Upcoming Primary Care Visit.

PURPOSE: To evaluate if nudges delivered by text message prior to an upcoming primary care visit can increase influenza vaccination rates. DESIGN: Randomized, controlled trial. SETTING: Two health systems in the Northeastern US between September 2020 and March 2021. SUBJECTS: 74,811 adults. INTERVENTIONS: Patients in the 19 intervention arms received 1-2 text messages in the 3 days preceding their appointment that varied in their format, interactivity, and content. MEASURES: Influenza vaccination. ANALYSIS: Intention-to-treat. RESULTS: Participants had a mean (SD) age of 50.7 (16.2) years; 55.8% (41,771) were female, 70.6% (52,826) were White, and 19.0% (14,222) were Black. Among the interventions, 5 of 19 (26.3%) had a significantly greater vaccination rate than control. On average, the 19 interventions increased vaccination relative to control by 1.8 percentage points or 6.1% (P = .005). The top performing text message described the vaccine to the patient as "reserved for you" and led to a 3.1 percentage point increase (95% CI, 1.3 to 4.9; P < .001) in vaccination relative to control. Three of the top five performing messages described the vaccine as "reserved for you." None of the interventions performed worse than control. CONCLUSIONS: Text messages encouraging vaccination and delivered prior to an upcoming appointment significantly increased influenza vaccination rates and could be a scalable approach to increase vaccination more broadly.

Do Sell-Side Stock Analysts Exhibit Escalation of Commitment?

This paper presents evidence that when an analyst makes an out-of-consensus forecast of a company's quarterly earnings that turns out to be incorrect, she escalates her commitment to maintaining an out-of-consensus view on the company. Relative to an analyst who was close to the consensus, the out-of-consensus analyst adjusts her forecasts for the current fiscal year's earnings less in the direction of the quarterly earnings surprise. On average, this type of updating behavior reduces forecasting accuracy, so it does not seem to reflect superior private information. Further empirical results suggest that analysts do not have financial incentives to stand by extreme stock calls in the face of contradictory evidence. Managerial and financial market implications are discussed.

Using Fresh Starts to Nudge Increased Retirement Savings.

We conducted a field experiment to study the effect of framing future moments in time as new beginnings (or "fresh starts"). University employees (N=6,082) received mailings with an opportunity to choose between increasing their contributions to a savings plan immediately or at a specified future time point. Framing the future time point in relation to a fresh start date (e.g., the recipient's birthday, the first day of spring) increased the likelihood that the mailing recipient chose to increase contributions at that future time point without decreasing their likelihood of increasing contributions immediately. Overall, fresh start framing increased retirement plan contributions in the eight months following the mailing. Our findings represent the first experimental demonstration of the benefits of fresh start framing in a consequential field setting.

Active choice, implicit defaults, and the incentive to choose.

Home-delivered prescriptions have no delivery charge and lower copayments than prescriptions picked up at a pharmacy. Nevertheless, when home delivery is offered on an opt-in basis, the take-up rate is only 6%. We study a program that makes active choice of either home delivery or pharmacy pick-up a requirement for insurance eligibility. The program introduces an implicit default for those who don't make an active choice: pharmacy pick-up without insurance subsidies. Under this program, 42% of eligible employees actively choose home delivery, 39% actively choose pharmacy pick-up, and 19% make no active choice and are assigned the implicit default. Individuals who financially benefit most from home delivery are more likely to choose it. Those who benefit least from insurance subsidies are more likely to make no active choice and lose those subsidies. The implicit default incentivizes people to make an active choice, thereby playing a key role in choice architecture.

Creating Exercise Habits Using Incentives: The Tradeoff between Flexibility and Routinization.

Habits involve regular, cue-triggered routines. In a field experiment, we tested whether incentivizing exercise routines-paying participants each time they visit the gym within a planned, daily two-hour window-leads to more persistent exercise than offering flexible incentives-paying participants each day they visit the gym, regardless of timing. Routine incentives generated fewer gym visits than flexible incentives, both during our intervention and after incentives were removed. Even among sub-groups that were experimentally induced to exercise at similar rates during our intervention, recipients of routine incentives exhibited a larger decrease in exercise after the intervention than recipients of flexible incentives.

Nudging: Progress to date and future directions.

Nudges influence behavior by changing the environment in which decisions are made, without restricting the menu of options and without altering financial incentives. This paper assesses past empirical research on nudging and provides recommendations for future work in this area by discussing examples of successful and unsuccessful nudges and by analyzing 174 articles that estimate nudge treatment effects. Researchers in disciplines spanning the behavioral sciences, using varied data sources, have documented that many different types of nudges succeed in changing behavior in a wide range of domains. Nudges that automate some aspect of the decision-making process have an average effect size, measured by Cohen's d, that is 0.193 larger than that of other nudges. Our analyses point to the need for future research to pay greater attention to (1) determining which types of nudges tend to be most impactful; (2) using field and laboratory research approaches as complementary methods; (3) measuring long-run effects of nudges; (4) considering effects of nudges on non-targeted outcomes; and (5) examining interaction effects among nudges and other interventions.

Do physician incentives increase patient medication adherence?

OBJECTIVE: To test the effectiveness of physician incentives for increasing patient medication adherence in three drug classes: diabetes medication, antihypertensives, and statins. DATA SOURCES: Pharmacy and medical claims from a large Medicare Advantage Prescription Drug Plan from January 2011 to December 2012. STUDY DESIGN: We conducted a randomized experiment (911 primary care practices and 8,935 nonadherent patients) to test the effect of paying physicians for increasing patient medication adherence in three drug classes: diabetes medication, antihypertensives, and statins. We measured patients' medication adherence for 18 (6) months before (after) the intervention. DATA COLLECTION/EXTRACTION METHODS: We obtained data directly from the health insurer. PRINCIPAL FINDINGS: We found no evidence that physician incentives increased adherence in any drug class. Our results rule out increases in the proportion of days covered by medication larger than 4.2 percentage points. CONCLUSIONS: Physician incentives of $50 per patient per drug class are not effective for increasing patient medication adherence among the drug classes and primary care practices studied. Such incentives may be more likely to improve measures under physicians' direct control rather than those that predominantly reflect patient behaviors. Additional research is warranted to disentangle whether physician effort is not responsive to these types of incentives, or medication adherence is not responsive to physician effort. Our results suggest that significant changes in the incentive amount or program design may be necessary to produce responses from physicians or patients.

How Are Preferences Revealed?

Revealed preferences are tastes that rationalize an economic agent's observed actions. Normative preferences represent the agent's actual interests. It sometimes makes sense to assume that revealed preferences are identical to normative preferences. But there are many cases where this assumption is violated. We identify five factors that increase the likelihood of a disparity between revealed preferences and normative preferences: passive choice, complexity, limited personal experience, third-party marketing, and intertemporal choice. We then discuss six approaches that jointly contribute to the identification of normative preferences: structural estimation, active decisions, asymptotic choice, aggregated revealed preferences, reported preferences, and informed preferences. Each of these approaches uses consumer behavior to infer some property of normative preferences without equating revealed and normative preferences. We illustrate these issues with evidence from savings and investment outcomes.