The effectiveness of health recommendations and treatments depends on the extent to which individuals follow them. For each individual, medical adherence involves an inter-temporal trade-off between expected future health benefits and immediate effort costs. Therefore variation in time preferences may help us understand why and not least which people fail to follow health recommendations and treatments. We develop a novel, yet simple real-effort time-preference task implemented via text message among pregnant women in South Africa and show that behavior in the task predicts medical adherence. We find that planning to do the task with delay significantly lowers self-reported adherence to the recommendation of taking daily iron supplements during pregnancy. There is weaker indication that delaying the task longer than initially planned also negatively affects adherence. Together our results suggest that even simple measures of time preferences could help predict medication adherence and is a first step toward designing targeted policies to help improve medication adherence, healthcare outcomes, and welfare.

This study examines the impact of human immunodeficiency virus (HIV)-specific laws criminalizing HIV non-disclosure, exposure, and transmission on voluntary testing, focusing on the role of HIV stigma. HIV criminalization signals state endorsement of discrimination against HIV-positive individuals, thereby amplifying stigma. I use a regression discontinuity design that exploits the enactment timing of legislation in Mali during a household survey offering voluntary HIV testing, where family members could infer who was tested and speculate that those tested were HIV-positive. Following the legislation, women’s testing uptake declined, especially in rural areas, with stronger effects among those with radios and without completed formal education. Women, being economically dependent on men, are vulnerable to HIV-related mistreatment from family members. Therefore, fear of being considered seropositive by family members might have more strongly discouraged women’s testing uptake compared with men’s.

Rapid population ageing and the digitalization of daily life have created a dual challenge: ensuring cognitive health while preventing digital exclusion among older adults. While the ‘use it or lose it’ hypothesis suggests that environmental stimulation protects against cognitive decline, international evidence regarding the causal impact of internet use on cognition remains mixed, particularly in developing contexts where digital adoption is uneven. This study addresses this gap by investigating the causal impact of internet use on cognitive abilities among middle-aged and older adults in China, while also exploring the heterogeneity of effects and potential underlying mechanisms. Utilizing three waves of panel data from the China Health and Retirement Longitudinal Study (CHARLS) with 40,438 observations, we employ instrumental variable (IV) estimation to address endogeneity and generalized random forests (GRFs) to estimate heterogeneous treatment effects. The results demonstrate that internet use significantly enhances cognitive abilities, with the IV estimates confirming a strong causal link. Notably, the GRF analysis reveals that these cognitive benefits are larger for rural residents, individuals with lower education levels and those who adopt the internet in middle age. Mechanism analyses indicate that these benefits are primarily driven by increased social interaction and reduced stress levels rather than changes in health behaviours. We conclude that digital inclusion serves as a critical non-medical intervention for healthy ageing, particularly in developing countries where it can help bridge cognitive disparities caused by socio-economic inequalities.

This study examines the relationship between cannabis and wine consumption, investigating whether these substances function as substitutes or complements. Using data from an online survey of 523 German wine consumers, including 215 cannabis users, we analyze consumption across four wine categories: white, red, rosé/sparkling, and sweet wines. To address potential bias from endogeneity, we employ an IV-Ordered Probit model with endogenous covariates—cannabis user/usage. The findings provide evidence of a complementary relationship: cannabis users report significantly higher wine consumption than non-users across most categories, except red wine. The effect is particularly pronounced for rosé/sparkling and sweet wines. More frequent cannabis use also correlates with increased wine consumption. Motivation-specific analyses reveal nuanced dynamics. Using cannabis for relaxation decreases wine consumption, suggesting substitution, while enhancement motives increase rosé/sparkling consumption. Social motives, however, show negative associations with these wines. Overall, results suggest that the nature of the cannabis–wine relationship depends on user motivations.

How have preventive and curative medical breakthroughs shaped life expectancy and the dispersion of age at death in the United States over the past century? We address this question by developing a life-cycle model in which both health and lifespan are endogenous. The model distinguishes between preventive innovations, which reduce the incidence of disease, and curative advances, which lower mortality risks associated with existing health conditions. Our quantitative analysis shows that while both types of medical innovation have contributed to increased life expectancy since 1935, curative advances have been the primary driver of the decline in the dispersion of age at death. Medical innovations have also improved welfare – measured in terms of a consumption-equivalent metric – by an average of 0.11% per year, with curative advances representing the most significant contribution. These findings are robust across different scenarios and parametrization strategies.

Until a few years ago, moderate alcohol consumption was thought to have (mild) beneficial effects on health. However, some recent studies have suggested that “there is no safe level” of alcohol intake. Consequently, public health institutions have responded by advising against any level of alcohol use and suggesting governments a number of policies to reduce overall alcohol consumption. Nonetheless, medical studies suffer from a variety of intrinsic limitations that could undermine the reliability of their findings, especially when focusing on low-intake levels. On the one hand, we show that the literature on alcohol consumption may suffer from publication bias; such a problem is known to be present in the scientific literature in general. On the other hand, we discuss other potential sources of bias, which are inevitable due to the infeasibility of randomized controlled trials. We assess a sample of articles for the presence of omitted variable bias, miscalculation of alcohol intake, use of linear in place of non-linear models, lack of validation of Mendelian randomization assumptions, and other possible weaknesses. We conclude that the claim that “there is no safe level” of alcohol intake is not sufficiently supported based on our current scientific knowledge.

College students gain a considerable amount of weight by consuming unhealthy food. Many universities adopt costly programs to alleviate this problem. We study the effect of a simple, inexpensive option: moving unhealthy items out of sight. The opportunity to investigate this intervention comes from the decision of a dining hall in the University of New Hampshire that relocated cookies from a main section in plain sight to an out-of-the way corner. The cost of cookies did not change, since the dining hall operates as an “all that you can eat” restaurant. Relative to pizza, a product that did not change location, the consumption of cookies dropped by up to 22% relative to their predicted level had the relocation not taken place. We see this as evidence that simple changes in design can nudge students towards healthy eating.

Using three waves (2011–15) of CHARLS data, we analyze the short-term effects of widowhood on cognitive function among older Chinese. Fixed-effect models show that widowhood has significant adverse effects on cognition for rural elders but not for urban ones. Furthermore, compared to rural men, rural women exhibit greater declines in cognition, especially in fluid cognition. We explore the possible mechanism from the neighborhood perspective. The results show that community sports and entertainment facilities and public services can effectively mitigate the negative impact of widowhood on cognitive function for rural widows. Sports and entertainment facilities can mainly enhance word recall ability, especially delayed word recall. Public services such as elderly health centers focusing on the healthcare function for the elderly can also improve the word recall ability of rural widows. On the other hand, family-based elderly care centers mainly increase the cognition ability of mental intactness.

The COVID-19 pandemic presents a remarkable opportunity to put to work all of the research that has been undertaken in past decades on the elicitation and structural estimation of subjective belief distributions as well as preferences over atemporal risk, patience, and intertemporal risk. As contributors to elements of that research in laboratories and the field, we drew together those methods and applied them to an online, incentivized experiment in the United States. We have two major findings. First, the atemporal risk premium during the COVID-19 pandemic appeared to change significantly compared to before the pandemic, consistent with theoretical results of the effect of increased background risk on foreground risk attitudes. Second, subjective beliefs about the cumulative level of deaths evolved dramatically over the period between May and November 2020, a volatile one in terms of the background evolution of the pandemic.

In a randomized field experiment, we show that a low-cost intervention, weekly email reminders, increases the weekly exercising frequency of gym members by 13%, with the effect being larger for class training (19%) than for free training (11%). We find that nearly all types of individuals benefit from the reminders (e.g., students, nonstudents, women, men, new members, recurring members), and this effect persists in a three-month posttreatment period. Furthermore, the increase in class visits is partly driven by an increase in the number of bookings of gym classes and a slight decrease in the share of bookings that are canceled. Limited attention and habit formation can best explain these results. In contrast to the increase in gym attendance, we do not find any effect on the duration and renewal of membership contracts.

We present a large scale study where a nationally representative sample of 1000 participants were asked to make real purchases within an online supermarket platform. The study captured the effect of price changes, and of the signposting of such changes, for breakfast cereals and soft drinks. We find that such taxes are an effective means of altering food purchasing, with a 20% rate being sufficient to make a significant impact if (and only if) the tax is signposted. Signposting represents a complementary “nudge” policy that could enhance the impact of the tax, though its effectiveness depends on the product category.

How does risk aversion change in wealth? To answer this question, we implemented a field experiment in the form of a free-to-play mobile game. Players made lottery choices at various points in the game and at different levels of in-game wealth. Since the game was designed as a closed economic system, that is, wealth could not be transferred into or out of the game, only in-game wealth was relevant for players’ choices. Analyzing the choices of over 2000 players, we find evidence for decreasing absolute risk aversion and decreasing relative risk aversion. We also find evidence of an “always safe” heuristic in a subgroup of decisions and observe a tendency of players to act according to the “hot hand fallacy”. Our research design allows us to exclude inertia and lets us analyze lottery stakes of significant size relative to in-game wealth. Our results render implications for theoretical research, empirical studies, and for the optimal design of financial products.

Governments across the world have implemented restrictive policies to slow the spread of COVID-19. Recommended face mask use has been a controversially discussed policy, among others, due to potential adverse effects on physical distancing. Using a randomized field experiment (N = 300), we show that individuals kept a significantly larger distance from someone wearing a face mask than from an unmasked person during the early days of the pandemic. According to an additional survey experiment (N = 456) conducted at the time, masked individuals were not perceived as being more infectious than unmasked ones, but they were believed to prefer more distancing. This result suggests that wearing a mask served as a social signal that led others to increase the distance they kept. Our findings provide evidence against the claim that mask use creates a false sense of security that would negatively affect physical distancing. Furthermore, our results suggest that behavior has informational content that may be affected by policies.

Loss framing and checklist formatting are two oft-cited tools for encouraging behavior change, but there is little causal evidence on their impact in field settings. We partnered with the City of Philadelphia to test the effectiveness of these tools to increase completion of the City’s wellness program. In our experiment, 5235 City employees and retirees were randomly assigned to receive one of four postcard versions (using a 2 × 2 design), whereby we varied both framing (gain or loss) and how instructions were provided (information only or information in checklist format). Our results suggest that neither loss framing nor the checklist formatting significantly influenced the likelihood that individuals would complete the wellness tasks, or how quickly they completed the tasks. We conclude that this specific form of employee behavior may be difficult to influence through the “passive” behavioral interventions we tested, and suggest that a more “active” approach may be required in such instances.

Access to information via social media is one of the biggest differentiators of public health crises today. During the early stages of the Covid-19 outbreak in January 2020, we conducted an experiment in Wuhan, China to assess the impact of viral social media content on pro-social and trust behaviours and preferences towards risk taking with known and unknown probabilities. Prior to the experiment, participants viewed one of two videos that had been widely and anonymously shared on Chinese social media: a central government leader visiting a local hospital and supermarket, or health care volunteers transiting to Wuhan. In a control condition, participants watched a Neutral video, unrelated to the crisis. Viewing one of the leadership or volunteer videos leads to higher levels of pro-sociality and lesser willingness to take risks in an ambiguous situation relative to the control condition. The leadership video, however, induces lower levels of trust. We provide evidence from two post-experiment surveys that the video’s impact on pro-sociality is modulated by influencing the viewer’s affective emotional state.

This study examines disparities in health and nutrition among native and Syrian refugee children in Turkey. To understand the need for targeted programs addressing child well-being among the refugee population, we analyze the Turkey Demographic and Health Survey (TDHS) – which provides representative data for a large refugee and native population. We find no evidence of a difference in infant or child mortality between refugee children born in Turkey and native children. However, refugee infants born in Turkey have lower birthweight and age-adjusted weight and height than native infants. When we account for a rich set of birth and socioeconomic characteristics that display substantial differences between natives and refugees, the gaps in birthweight and age-adjusted height persist, but the gap in age-adjusted weight disappears. Moreover, the remaining gaps in birthweight and anthropometric outcomes are limited to the lower end of the distribution. The observed gaps are even larger for refugee infants born before migrating to Turkey, suggesting that the remaining deficits reflect conditions in the source country before migration rather than deficits in access to health services within Turkey. Finally, comparing children by the country of their first trimester, we find evidence of the detrimental effects of stress exposure during pregnancy.

Since 2006, Rwanda has experienced a substantial rise in the facility-based delivery (FBD) rate, attributed to various health initiatives. This paper investigates the impact of multiple health reforms on maternal service utilization and neonatal mortality rates. Employing a difference-in-differences framework utilizing geographical variation in the baseline FBD rate, our estimates indicate a 10–17 percentage point increase in FBD and a 0.15–0.18 times increase in the number of antenatal care visits. While our analysis indicates some evidence of a reduction in neonatal mortality rates, the findings are inconclusive. Nevertheless, our results suggest that the effect of the reforms on neonatal mortality rates was weakly intensified for those residing near district hospitals providing care for complicated pregnancies.

The consequences of legal access to medical marijuana for individuals' well-being are controversially assessed. We contribute to the discussion by evaluating the impact of the introduction of medical marijuana laws across US states on self-reported mental health considering different motives for cannabis consumption. Our analysis is based on BRFSS survey data from close to eight million respondents between 1993 and 2018 that we combine with information from the NSDUH to estimate individual consumption propensities. We find that eased access to marijuana through medical marijuana laws reduce the reported number of days with poor mental health for individuals with a high propensity to consume marijuana for medical purposes and for those individuals who likely suffer from frequent pain.

Using the public-use files of the Canadian Community Health Survey and a difference-in-differences methodology, we estimate the impact of a universal income transfer (the Universal Child Care Benefit) on food insecurity, separately for adults and children within households. The income transfer reduced the risk of overall food insecurity by 20% at the child level, and the effect was larger in households with lower education or income. The transfer also reduced the likelihood of moderate/severe food insecurity among adults in single-parent families, as well as adults and children in households with secondary education or less. These findings withstand several robustness checks.

Exploiting the fact that hypertension is diagnosed when a person’s blood pressure reading exceeds a medically specified threshold (90 mmHg for diastolic blood pressure or 140 mmHg for systolic blood pressure), this study estimates the effect of a first-ever hypertension diagnosis on Chinese adults’ alcohol consumption using a two-dimensional regression discontinuity design. Analyzing data on 10,787 adults from the China Health and Nutrition Survey, our estimation reveals that hypertension diagnoses based on diastolic blood pressure readings exert a number of desirable effects. Hypertensive adults’ drinking frequency and the incidence of excessive drinking among them were reduced by 1.2 times/week and 17.9 percentage points, respectively, about three years after the diagnosis. Meanwhile, their beer and Chinese spirits (Baijiu) intakes were reduced by 518.6 ml/week and 194.8 ml/week, respectively. Interestingly, we also found modest evidence that hypertension diagnoses based on diastolic blood pressure readings increase Chinese adults’ wine intake, suggesting a substitution pattern upon hypertension diagnoses. In contrast, based on systolic blood pressure readings, no significant effects of hypertension diagnoses on alcohol consumption were found.