Lottery-based Incentive Research Articles

A Smartphone-Based Shopping Mall Walking Program and Daily Walking Steps

Because shopping malls are considered safe places for walking, several mall walking programs have been developed. Research on the association between the use of walking programs and the number of daily steps taken is limited. To evaluate the association between use of a smartphone-based shopping mall walking program and daily steps taken after the COVID-19 pandemic. This cohort study evaluated a nationwide longitudinal data set of 217 344 registered smartphone app users at least 18 years of age residing in Japan. Daily step counts were collected from January 1 to December 31, 2021. The mall walking program Mall Challenge integrated a global positioning system with a smartphone app's incentive system to reward achieving a goal of 1000 daily steps with lottery-based coupons to win from 0 to 500 shopping points (1 point equaled 1 yen or approximately US $0.01). Daily step records were collected from the smartphone app's walking program and adjusted for gender and age. Multilevel analyses using mixed-effect linear regression models were used to estimate the coefficients for the association between daily participation in the walking program and daily step counts. Cross-level interaction terms of age and gender by walking program participation were included in one model. Among the 217 344 registered mall app users (23 638 110 daily step records; 154 616 [71.1%] women; 18 014 [8.3%] participants 65 years or older, and 199 330 [91.7%] adults younger than 65 years), the mean (SD) daily steps were 7415 (4686) on walking program participation days and 5281 (4339) on days without participation in the program. Walking program participation days were associated with 1219 additional daily steps (95% CI, 1205-1232) compared with nonparticipation days after adjusting for gender and age. By geographic region, participation in the walking program was associated with 1130 (95% CI, 1113-1146) more steps in rural malls, 1403 (95% CI, 1379-1428) more steps in suburban malls, and 1433 (95% CI, 1408-1457) more steps in urban malls than nonparticipation. Moreover, participation in the walking program was associated with 1422 (95% CI, 1405-1439) more steps in large malls and 1059 (95% CI, 1041-1077) more steps in small malls compared with nonparticipation. Regarding cross-level interactions, women were associated with walking 728 (95% CI, 698-758) more steps than men, and older adults were associated with walking 228 (95% CI, 183-273) more steps than younger adults on walking program participation days. This cohort study found that the use of a smartphone-based mall walking program combined with physical shopping mall facilities and lottery-based digital incentive coupons may motivate people to increase their daily number of walking steps.

Evaluation of the Effectiveness of Behavioral Economic Incentive Programs for Goal Achievement on Healthy Diet, Weight Control and Physical Activity: A Systematic Review and Network Meta-analysis.

Healthy diet, weight control and physical activity to reduce obesity can be motivated by financial incentives (FI). Behavioral-economic approaches may improve the incentivization effectiveness. This study compares and ranks the effectiveness of standard and behavioral incentivization for healthy diet, weight control, and physical activity promotion. To investigate whether behavioral-economic insights improve incentivization effectiveness. A systematic search of Medline and Scopus was performed from database inception to December 2020. Study characteristics, program designs, and risk ratio (RR) were extracted. A two-stage network meta-analysis pooled and ranked intervention effects. There were 35 eligible RCTs. For diet-weight control, standard FI, deposit contract (deposit), lottery-based incentive (lottery), and standard-FI + lottery increased goal achievement compared to no-FI but only deposit was statistically significant with pooled RRs and 95% confidence intervals (CI) of 1.21 (0.94, 1.56), 1.79 (1.04, 3.05), 1.45 (0.99, 2.13), and 1.73 (0.83, 3.63). For physical activity, standard-FI, deposit, and lottery significantly increased goal achievement compared to no-FI, with pooled RRs of 1.38 (1.13, 1.68), 1.63 (1.24, 2.14) and 1.43 (1.14, 1.80), respectively. In a follow-up period for physical activity, only deposit significantly increased goal achievement compared to no-FI, with pooled RRs of 1.39 (1.11, 1.73). Deposit, followed by lottery, were best for motivating healthy diet, weight control and physical activity at program end. Post-intervention, deposit then standard-FI were best for motivating physical activity. Behavioral insights can improve incentivization effectiveness, although lottery-based approaches may offer only short-term benefit regarding physical activity. However, the imprecise intervention effects were major concerns.

Assessing the Impact of Vaccine Lotteries on COVID-19 Vaccination Rates in the United States in 2021.

We assessed the impact of COVID-19 vaccine lottery programs on COVID-19 vaccination coverage using Centers for Disease Control and Prevention‒reported first-dose vaccination administration rates for the population aged 18 years and older for 19 states that adopted lottery-based incentive programs. We did not find evidence of increased first-dose vaccination rates following lottery announcements across participating states and, therefore, find little justification for the use of COVID-19 vaccination lotteries to increase vaccination rates. (Am J Public Health. 2022;112(8):1130-1133. https://doi.org/10.2105/AJPH.2022.306863).

Lottery-Based Incentive in Ohio and COVID-19 Vaccination Rates

This study assesses changes in COVID-19 vaccination rates before and after the Ohio vaccine lottery announcement compared with national rates to control for the expansion of vaccine indications to adolescents.

Promoting routine syphilis screening among men who have sex with men in China: study protocol for a randomised controlled trial of syphilis self-testing and lottery incentive

BackgroundMen who have sex with men (MSM) bear a high burden of syphilis infection. Expanding syphilis testing to improve timely diagnosis and treatment is critical to improve syphilis control. However, syphilis testing rates remain low among MSM, particularly in low- and middle-income countries. We describe the protocol for a randomised controlled trial (RCT) to assess whether provision of syphilis self-testing services can increase the uptake of syphilis testing among MSM in China.MethodsFour hundred forty-four high-risk MSM will be recruited online and randomized in a 1:1:1 ratio to (1) standard syphilis self-testing arm; (2) a self-testing arm program enhanced with crowdsourcing and a lottery-based incentive, and (3) a standard of care (control). Self-testing services include a free syphilis self-test kit through the mail at monthly intervals. Participants in the lottery incentive arm will additionally receive health promotion materials generated from an open crowdsourcing contest and be given a lottery draw with a 10% chance to win 100 RMB (approximately 15 US Dollars) upon confirmed completion of syphilis testing. Syphilis self-test kits have step-by-step instructions and an instructional video. This is a non-blinded, open-label, parallel RCT. Participants in each arm will be followed-up at three and 6 months through WeChat (a social media app like Facebook messenger). Confirmation of syphilis self-test use will be determined by requiring participants to submit a photo of the used test kit to study staff via secure data messaging. Both self-testing and facility-based testing will be ascertained by sending a secure photographic image of the completed kit through an existing digital platform. The primary outcome is the proportion of participants who tested for syphilis in the past 3 months.DiscussionFindings from this study will provide much needed insight on the impact of syphilis self-testing on promoting routine syphilis screening among MSM. The findings will also contribute to our understanding of the safety, effectiveness and acceptability of syphilis self-testing. These findings will have important implications for self-testing policy, both in China and internationally.Trial registrationChiCTR1900022409 (10 April, 2019).

Text messaging and lottery incentive to improve colorectal cancer screening outreach at a community health center: A randomized controlled trial.

Efforts to boost colorectal cancer (CRC) screening rates in underserved populations have been limited by effectiveness and scalability. We evaluate the impact of adding a lottery-based financial incentive to a text messaging program that asks patients to opt-in to receive mailed fecal immunochemical testing (FIT). This is a two-arm pragmatic randomized controlled trial at a community health center in Southwest Philadelphia from April to July 2017. We included CRC screening-eligible patients between ages 50-74years who had a mobile phone, active health insurance, and at least one visit to the clinic in the past 12months. Patients received a text message about CRC screening with the opportunity to opt-in to receive mailed FIT. They were randomized 1:1 to the following: (1) text messaging outreach alone (text), or (2) text messaging with lottery for a 1-in-5 chance of winning $100 after FIT completion (text+lottery). The primary outcome was the percentage of patients completing the mailed FIT within 3months of initial outreach. 281 patients were included in the intent-to-treat analysis. The FIT completion rate was 12.1% (95% CI, 6.7%-17.5%) in the text message arm and 12.1% (95% CI, 6.7%-17.5%) in the lottery arm, with no statistical difference between arms. The majority of post-intervention interview respondents found text messaging to be acceptable and convenient. Opt-in text messaging is a feasible option to promote the uptake of mailed FIT screening, but the addition of a lottery-based incentive did not improve completion rates. Trial Registration: clinicaltrials.gov (NCT03072095).

Effect of Escalating Financial Incentive Rewards on Maintenance of Weight Loss

Identifying effective strategies for treating obesity is a public health priority. To test an escalating lottery-based incentive tied to daily self-weighing for weight loss maintenance. This 2-phase, 2-arm randomized clinical trial enrolled participants aged 30 to 80 years with an initial body mass index (calculated as weight in kilograms divided by height in meters squared) of 30.0 to 45.0 who lost at least 5 kg during 4 to 6 months in a national online weight management program. Study investigators and outcomes assessors were blinded to participant groups. Data were collected and analyzed from May 23, 2016, through November 13, 2017, based on intention to treat. All participants were advised to weigh themselves daily, with a goal of 6 or more days per week, and received text messaging feedback on their performance. Incentive group participants were eligible for a lottery-based incentive worth an expected value of $3.98 in week 1 that escalated by $0.43 each week they achieved their self-weighing goal during months 1 to 6 (phase 1), followed by no incentives during months 7 to 12 (phase 2). The primary outcome was weight change at the end of phase 1. Secondary outcomes included weight change at the end of phase 2 and changes in self-reported physical activity and eating behaviors. A total of 258 participants (128 in the incentive group and 130 in the control group) had a mean (SD) age of 48.0 (10.5) years and mean (SD) body mass index of 32.1 (3.9); 225 (87.2%) were women; 235 (91.1%) were white; and 102 (39.5%) had an annual income of at least $100 000. Weight measurement was transmitted by 250 participants (96.9%) at 6 months and 227 (88.0%) at 12 months. The percentage of weeks that incentive and control participants achieved a mean self-weighing of at least 6 times was 85.3% vs 75.8%, respectively (P = .002) in phase 1 and 37.7% vs 50.2%, respectively (P = .009) in phase 2. Mean weight changes at the end of phase 1 were -1.1 (95% CI, -2.1 to -0.1) kg in the incentive group and -1.9 (95% CI, -2.9 to -0.8) kg in the control group, with a mean difference of 0.7 (95% CI, -0.7 to 2.2) kg (P = .30 for comparison). At the end of phase 2, mean weight changes were 0.2 (95% CI, -1.2 to 1.7) kg in the incentive group and -0.6 (95% CI, -2.0 to 0.8) kg in the control group, with a mean difference of 0.8 (95% CI, -1.2 to 2.8) kg (P = .41 for comparison). Compared with an active control condition of weekly messages, escalating lottery-based incentives transiently increased rates of self-weighing but did not significantly enhance weight loss maintenance. ClinicalTrials.gov identifier: NCT01900392.

Use of Lotteries for the Promotion of Voluntary Medical Male Circumcision Service: A Discrete-Choice Experiment among Adult Men in Tanzania.

Voluntary medical male circumcision (VMMC) is effective in reducing the risk of human immunodeficiency virus (HIV). However, countries like Tanzania have high HIV prevalence but low uptake of VMMC. We conducted a discrete-choice experiment to evaluate the preferences for VMMC service attributes in a random sample of 325 men aged 18 years or older from the general population in 2 Tanzanian districts, Njombe and Tabora. We examined the preference for financial incentives in the form of a lottery ticket or receiving a guaranteed transport voucher for attendance at a VMMC service. We created a random-parameters logit model to account for individual preference heterogeneity and a latent class analysis model for identifying groups of men with similar preferences to test the hypothesis that men who reported sexually risky behaviors (i.e., multiple partners and any condomless sex in the past 12 months) may have a preference for participation in a lottery-based incentive. Most men preferred a transport voucher (84%) over a lottery ticket. We also found that offering a lottery-based financial incentive may not differentially attract those with greater sexual risk. Our study highlights the importance of gathering local data to understand preference heterogeneity, particularly regarding assumptions around risk behaviors.

Financial incentive strategies for maintenance of weight loss: results from an internet-based randomized controlled trial

Background/objectiveFinancial incentives can improve initial weight loss; we examined whether financial incentives can improve weight loss maintenance.Subjects/methodsParticipants aged 30–80 years who lost at least 5 kg during the first 4–6 months in a nationally available commercial weight loss program were recruited via the internet into a three-arm randomized trial of two types of financial incentives versus active control during months 1–6 (Phase I) followed by passive monitoring during months 7–12 (Phase II). Interventions were daily self-weighing and text messaging feedback alone (control) or combined with a lottery-based incentive or a direct incentive. The primary outcome was weight change 6 months after initial weight loss. Secondary outcomes included weight change 12 months after initial weight loss (6 months after cessation of maintenance intervention), and self-reported physical activity and eating behaviors.ResultsOf 191 participants randomized, the mean age was 49.0 (SD = 10.5) years and weight loss prior to randomization was 11.4 (4.7) kg; 92% were women and 89% were White. Mean weight changes during the next 6 months (Phase I) were: lottery −3.0 (5.8) kg; direct −2.8 (5.8) kg; and control −1.4 (5.8) kg (all pairwise comparisons p > 0.1). Weight changes through the end of 12 months post-weight loss (Phase II) were: lottery −1.8 (10.5) kg; direct −0.7 (10.7) kg; and control −0.3 (9.4) kg (all pairwise comparisons p > 0.1). The percentages of participants who maintained their weight loss (defined as gaining ≤1.36 kg) were: lottery 79%, direct 76%, and control 67% at 6 months and lottery 66%, direct 62%, and control 59% at 12 months (all pairwise comparisons p > 0.1). At 6 and 12 months after initial weight loss, changes in self-reported physical activity or eating behaviors did not differ across arms.ConclusionsCompared with the active control of daily texting based on daily home weighing, lottery-based and direct monetary incentives provided no additional benefit for weight loss maintenance.

Testing strategies to increase saving in individual development account programs

A series of randomized field experiments tests whether saving rates in a federally funded, matched, savings program for low-income families – the Individual Development Account program – can be improved through insights from behavioral economics. We test the impact of: (a) holding savers accountable for making savings deposits, (b) increasing the frequency with which deposits are made, and (c) introducing a lottery-based incentive structure. We find small, positive effects of the frequency and lottery treatments on cumulative savings. We investigate reasons for the modest effects of the treatments using interviews with study participants.

Feasibility of an incentive scheme to promote active travel to school: a pilot cluster randomised trial

BackgroundIn Great Britain, 19% of trips to primary school within 1 mile, and 62% within 1–2 miles, are by car. Active travel to school (ATS) offers a potential source of moderate-to-vigorous physical activity (MVPA). This study tested the feasibility of an intervention to promote ATS in 9–10 year olds and associated trial procedures.MethodsA parallel cluster randomised pilot trial was conducted over 9 weeks in two schools from a low-income area in northeast England. Measures included daily parental ATS reports (optionally by SMS) and child ATS reports, as well as accelerometry (ActiGraph GT3X+). At baseline, all children were asked to wear the accelerometer for the same week; in the post-randomisation phase, small subsamples were monitored each week. In the 2 weeks when a child wore the accelerometer, parents also reported the start and finish times of the journey to school. The intervention consisted of a lottery-based incentive scheme; every ATS day reported by the parent, whether by paper or SMS, corresponded to one ticket entered into a weekly £5 voucher draw. Before each draw session, the researcher prepared the tickets and placed them into an opaque bag, from which one was randomly picked by the teacher at the draw session.ResultsFour schools replied positively (3.3%, N = 123) and 29 participants were recruited in the two schools selected (33.0%, N = 88). Participant retention was 93.1%. Most materials were returned on time: accelerometers (81.9%), parental reports (82.1%) and child reports (97.9%). Draw sessions lasted on average 15.9 min (IQR 10–20) and overall session attendance was 94.5%. Parent-child report agreement regarding ATS was moderate (k = 0.53, CI 95% 0.45; 0.60). Differences in minutes of accelerometer-assessed MVPA between parent-reported ATS and non-ATS trips were assessed during two timeframes: during the journey to school based on the times reported by the parent (U = 390.5, p < 0.05, 2.46 (n = 99) vs 0.76 (n = 13)) and in the hour before classes (U = 665.5, p < 0.05, 4.99 (n = 104) vs 2.55 (n = 19)). Differences in MVPA minutes between child-reported ATS and non-ATS trips were also significant for each of the timeframes considered (U = 596.5, p < 0.05, 2.40 (n = 128) vs 0.81 (n = 15) and U = 955.0, p < 0.05, 4.99 (n = 146) vs 2.59 (n = 20), respectively).ConclusionsData suggest the feasibility of an ATS incentive scheme and of most trial procedures. School recruitment stood out as requiring further piloting.Trial registrationClinicalTrials.gov: NCT02282631. Registered 5th September 2014.

The design and conduct of Keep It Off: An online randomized trial of financial incentives for weight-loss maintenance.

Background Obesity continues to be a serious public health challenge. Rates are increasing worldwide, with nearly 70% of the US adults overweight or obese, leading to increased clinical and economic burden. While successful approaches for achieving weight loss have been identified, techniques for long-term maintenance of initial weight loss have largely been unsuccessful. Financial incentive interventions have been shown in several settings to be successful in motivating participants to adopt healthy behaviors. Purpose Keep It Off is a three-arm randomized controlled trial that compares the efficacy of a lottery-based incentive, traditional direct payment incentive, and control of daily feedback without any incentive for weight-loss maintenance. This design allows comparison of a traditional direct payment incentive with one based on behavioral economic principles that consider the underlying psychology of decision-making. Methods Participants were randomized in a 2:1 ratio for each active arm relative to control, with a targeted 188 participants in total. Eligible participants were those aged 30-80 who lost at least 11 lb (5 kg) during the first 4 months of participation in Weight Watchers, a national weight-loss program, with whom we partnered. The interventions lasted 6 months (Phase I); participants were followed for an additional 6 months without intervention (Phase II). The primary outcome is weight change from baseline to the end of Phase I, with the change at the end of Phase II a key secondary endpoint. Keep It Off is a pragmatic trial that recruited, consented, enrolled, and followed patients electronically. Participants were provided a wireless weight scale that electronically transmitted daily self-monitored weights. Weights were verified every 3 months at a Weight Watchers center local to the participant and electronically transmitted. Results Using the study web-based platform, we integrated recruitment, enrollment, and follow-up procedures into a digital platform that required little staff effort to implement and manage. We randomized 191 participants in less than 1 year. We describe the design of Keep It Off and implementation of enrollment. Lessons Learned We demonstrated that our pragmatic design was successful in rapid accrual of participants in a trial of interventions to maintain weight loss. Limitations Despite the nationwide reach of Weight Watchers, the generalizability of study findings may be limited by the characteristics of its members. The interventions under study are appropriate for settings where an entity, such as an employer or health insurance company, could offer them as a benefit. Conclusions Keep It Off was implemented and conducted with minimal staff effort. This study has the potential to identify a practical and effective weight-loss maintenance strategy.

Testing Strategies to Increase Saving and Retention in Individual Development Account Programs

In a series of field experiments we test whether saving and retention rates in a federally funded, matched savings program for low-income families – the Individual Development Account (IDA) program – can be improved through the introduction of program features inspired by behavioral economics. We partnered with eight IDA programs across the U.S. who agreed to randomly assign participants to different experimental conditions. We test the impact of four revenue-neutral changes in key program features: a) holding savers accountable for making savings deposits through phone calls before and after the deposit deadline, b) an increase in the frequency with which deposits are made from monthly to bi-weekly, c) the introduction of a lottery-based incentive structure, whereby match rates are determined in part by a lottery at the time of each deposit, and d) an increase in the savings match from $2 for every $1 saved to $4 for every $1 saved when half of the savings goal was reached. None of our four interventions had the desired effect of increasing savings. To explain the null findings, we speculate that liquidity constraints, rather than cognitive biases, were the primary impediment to saving.

An endogenous lottery-based incentive mechanism to promote off-peak usage in congested transit systems

In this paper, we evaluate a lottery-based revenue-neutral incentive mechanism to reduce the congestion in urban transportation systems. Specifically, we test the use of random lottery-based reward schemes to promote public transit usage during off‐peak periods. We derive the theoretical equilibrium for this decision-making game and test the validity of the proposed mechanism through monetized laboratory experiments. We use methods from experimental economics to investigate the behavioral assumptions within such an incentive-based mechanism. We find counterintuitive results where a Pure Nash Equilibrium explains behavior in one regime and Quantal Response Equilibrium explains behavior in another regime. Specifically, there is no shift to off-peak periods when the expected value of traveling in the off-peak is less than that at peak, which is explained by a Pure Nash Equilibrium. However, there is a substantial shift to the off-peak period when the expected value of traveling in the off-peak is larger than that of the peak, but much less than that predicted by a Pure Nash Equilibrium. The Quantal Response Equilibrium performs reasonably well in this condition, and we conclude that risk attitudes play a significant role in explaining behavior in lottery-based incentive mechanisms. This study, which relies on the gamification of travel behavior, finds that the proposed mechanism can provide a sustainable shift in users’ choices.

Improving Treatment Integrity in a Human Service Setting Using Lottery-Based Incentives

The present study was conducted to improve implementation fidelity of discrete trial training procedures. Three participants were selected from a special education school providing services for students with intellectual disabilities. Staff behaviors measured included the correct implementation of a prompt hierarchy, the accuracy of data recorded, the correct delivery of prompts, and whether procedures were correctly set up for the following day's activities. Intervention consisted of daily verbal and graphic feedback and a lottery-based incentive system in which staff had to perform at a set goal level for the week in order to be eligible for entry into a drawing. A multiple-baseline-across-participants design was utilized to evaluate the effects of the intervention package, and integrity improved consistently for all participants during the intervention.

Randomized trial of lottery-based incentives to improve warfarin adherence

Poor adherence to medications is a major cause of morbidity and inadequate drug effectiveness. Efforts to improve adherence have typically been either ineffective or too complex to implement in clinical practice. Lottery-based incentive interventions could be a scalable approach to improving adherence. This was a randomized, controlled clinical trial of a daily lottery-based incentive in patients on warfarin stratified by baseline international normalized ratio (INR). The trial randomized 100 patients to either a lottery-based incentive or no lottery intervention. Main outcome was out-of-range INRs. Over 6 months, the overall percentage of out-of-range INRs did not differ between the 2 arms (mean 23.0% in lottery arm and 25.9% in control arm, adjusted odds ratio [OR] 0.93, 95% CI 0.62-1.41). However, among the a priori subgroup with a baseline INR below therapeutic range, there was a significant reduction in out-of-range INR in the lottery arm versus the control arm (adjusted OR 0.39, 95% CI 0.25-0.62), whereas there was no such effect among those with therapeutic INRs at baseline (adjusted OR 1.26, 95% CI, 0.76-2.09, P value for interaction = .0016). Among those with low INR at baseline, there was a nonsignificant 49% reduction in the odds of nonadherence with the intervention (OR 0.51, 95% CI 0.23-1.14). Although a lottery-based intervention was not associated with a significant improvement in anticoagulation control among all study participants, it improved control among an a priori group of patients at higher risk for poor adherence.

A test of financial incentives to improve warfarin adherence

BackgroundSub-optimal adherence to warfarin places millions of patients at risk for stroke and bleeding complications each year. Novel methods are needed to improve adherence for warfarin. We conducted two pilot studies to determine whether a lottery-based daily financial incentive is feasible and improves warfarin adherence and anticoagulation control.MethodsVolunteers from the University of Pennsylvania Anticoagulation Management Center who had taken warfarin for at least 3 months participated in either a pilot study with a lottery with a daily expected value of $5 (N = 10) or a daily expected value of $3 (N = 10). All subjects received use of an Informedix Med-eMonitor™ System with a daily reminder feature. If subjects opened up their pill compartments appropriately, they were entered into a daily lottery with a 1 in 5 chance of winning $10 and a 1 in 100 chance of winning $100 (pilot 1) or a 1 in 10 chance of winning $10 and a 1 in 100 chance of winning $100 (pilot 2). The primary study outcome was proportion of incorrect warfarin doses. The secondary outcome was proportion of INR measurements not within therapeutic range. Within-subject pre-post comparisons were done of INR measurements with comparisons with either historic means or within-subject comparisons of incorrect warfarin doses.ResultsIn the first pilot, the percent of out-of-range INRs decreased from 35.0% to 12.2% during the intervention, before increasing to 42% post-intervention. The mean proportion of incorrect pills taken during the intervention was 2.3% incorrect pills, compared with a historic mean of 22% incorrect pill taking in this clinic population. Among the five subjects who also had MEMS cap adherence data from warfarin use in our prior study, mean incorrect pill taking decreased from 26% pre-pilot to 2.8% in the pilot. In the second pilot, the time out of INR range decreased from 65.0% to 40.4%, with the proportion of mean incorrect pill taking dropping to 1.6%.ConclusionA daily lottery-based financial incentive demonstrated the potential for significant improvements in missed doses of warfarin and time out of INR range. Further testing should be done of this approach to determine its effectiveness and potential application to both warfarin and other chronic medications.