Advise others before making your own food choices: an experimental investigation (with Arthur E. Attema & Werner B.F. Brouwer) [pdf]
Abstract: Construal level theory (CLT) suggests that giving advice to others places an individual at a larger social distance from their own choices and consequently fosters rationality. This research further explores whether this fostered rationality affects one's own food choices. Specifically, we investigate whether and how letting people advise others on food choices affects their subsequent own choices. We conducted a laboratory experiment with 182 university students, where the treatment group was asked to give advice to another participant on snack food before making their own choices, while the control group directly made their own choices. Controlling for state and demographic variables, we find that advising others before making their own choices significantly increased the probability of choosing healthy food for themselves by around 17 percentage points. This effect was especially marked among females who advised or would advise others to eat healthy. Additionally, we measured the time preference for money, healthy food, and unhealthy food, and we found the treatment is more effective for individuals who are more patient with unhealthy food than healthy food. Our main finding implies that placing oneself in an other-oriented mindset, i.e. thinking about advising others before making one's own decisions, could benefit their own subsequent decisions. The significant treatment effect also reflects that asking individuals to advise others before making their own food choices could be a strategy for promoting healthy eating.
Time and lexicographic preferences in the valuation of EQ-5D-Y with time trade-off methodology (with Stefan A. Lipman, Koonal K. Shah & Arthur E. Attema) [Link] The European Journal of Health Economics, 24(2), 293‑305.
Abstract: In the valuation of EQ-5D-Y-3L, adult respondents are asked to complete composite time trade-off (cTTO) tasks for a 10-year-old child. Earlier work has shown that cTTO utilities elicited in such a child perspective are generally higher than when adults take their own perspective. We explore how differences in time preference in child and adult perspectives could explain this effect. Furthermore, as cTTO valuation in a child perspective involves explicit consideration of immediate death for a child, we also consider how cTTO utilities could be affected by decision-makers lexicographically avoiding death in children. We report the results of an experiment in which 219 respondents valued 5 health states in both adult and child perspectives with either a standard cTTO or a lead-time TTO only approach, in which immediate death is less focal. Time preferences were measured in both perspectives. Our results suggest that utilities were lower when lead-time TTO, rather than cTTO, was used. We find large heterogeneity in time preference in both perspectives, with predominantly negative time preference. The influence of time preferences on utilities, however, was small, and correcting for time preferences did not reduce differences between utilities elicited in both perspectives. Surprisingly, we found more evidence for differences in utilities between adult and child perspectives when lead-time TTO was used. Overall, these results suggest that time and lexicographic preferences affect time trade-off valuation in child and adult perspectives, but are not the explanation for differences between these perspectives. We discuss the implications of our findings for EQ-5D-Y-3L valuation.
Is Episodic Future Thinking effective in mitigating the influence of time preference in time trade-off? (with Zhongyu Lang, Stefan A. Lipman, Bradley Sugden, Kim Rand & Arthur E. Attema) [pdf]
Abstract:
Objectives: The composite time trade-off (cTTO) method has been found to be influenced by time preferences for future life years, which typically results in a downward bias on cTTO utilities without adjustment. Contrary to prior research that adjusted for this distortion ex-post, this study takes an ex-ante approach, using Episodic Future Thinking (EFT), to potentially prevent time preference distortion. We aim to investigate the effect of EFT on time preference and cTTO utilities compared to using alternative methods.
Methods: A total of 150 participants from the UK general public were recruited for interviewer-led online interviews and randomly assigned to either the control or treatment group. In the control group, they were asked to recall recent memories using the Episodic Recent Thinking (ERT) protocol, serving as filler tasks; in the treatment group, they were asked to imagine life in the next 10 to 20 years, i.e. using an EFT protocol. Afterwards, respondents were asked to value seven EQ-5D-5L health states with cTTO tasks, followed by a nonparametric method to measure time preference.
Results: We observed a similar pattern of time preference across the two groups, with the majority discounting positively. EFT did not significantly affect time preference. In addition, the difference between cTTO utilities mitigated by EFT and those adjusted using the ex-post approach for time preference is minimal.
Conclusions: In conclusion, EFT does not seem to mitigate time preference for life years and has negligible effect on cTTO utilities, necessitating alternative strategies for reducing bias in health utilities.
Increasing the Minimum Legal Drinking Age: impacts on adolescent alcohol consumption (with Elisa de Weerd, Hans van Kippersluis, John Cawley, Ruud Roodbeen, Karin Monshouwer, & Saskia van Dorsselaer) [Slides]
Abstract: A common strategy to limit alcohol consumption among adolescents is to restrict the purchase or use of alcohol using a minimum legal drinking age (MLDA). In the last decades, various countries in Europe have raised their MLDA from 16 to 18. This paper studies the effects of an increase in the MLDA on alcohol consumption exploiting the 2014 MLDA increase from 16 to 18 in the Netherlands. Using self-reported bi-annual survey data of school-aged children, we find that the MLDA has a limited impact on adolescent drinking behavior in the Netherlands. MLDA at 16 did not significantly influence alcohol prevalence among Dutch adolescents. Before the policy change, the MLDA at 16 reduced the incidence of binge drinking at that age by about 5 percent. However, after raising the MLDA from 16 to 18, we observe that binge drinking at age 16 increased by 18 percent, though this effect is only significant at the 10% level. This mixed impact may be attributed to behavioral differences between boys and girls in response to the policy change. This paper also examines the mechanisms through which the MLDA restricts the alcohol access and consumption. We find that the MLDA legislation does not severely limit Dutch adolescents' access to alcohol and therefore cannot fully explain the relationship between age and drinking behavior. We supplement our analysis with large-scale consumption data and discover that, although age-related difficulties in obtaining alcohol and parental permission generally align with the legal provisions of the MLDA, overall enforcement of the MLDA in the Netherlands is relatively low, with an effectiveness rate of only around 50 percent. Additionally, Dutch adolescents might cross borders to binge drink in countries with lower MLDAs. After raising the MLDA to 18, there was little change in adolescents' risk perceptions and behaviors regarding the frequency and intensity of drinking.
A head-to-head comparison of methods for measuring time preference (with Arthur E. Attema & Stefan A. Lipman)
Abstract
Objectives: This study aims to compare the performance of various time preference elicitation methods between the monetary and health domains. Specifically, we evaluated their feasibility, internal validity, and concurrent validity within each domain, and predictive validity of these methods on health behaviors. Additionally, we are interested in detecting which methods can potentially useful that were not yet applied to health.
Methods: We identified five methods based on a ranking of methodological and theoretical importance for a head-to-head comparison in measuring time preferences (i) the direct method (Attema et al., 2012), (ii) the non-parametric method (Abdellaoui et al., 2016; Lipman et al., 2019), (iii) the onset of disease method (Attema and Versteegh, 2013), (iv) patience auctions (Olivola and Wang, 2016), and (v) the monetary choice questionnaire (Kirby and Maraković, 1995). Methods (i), (ii), and (iii) are health-framed, while methods (iv) and (v) are non-health methods. A total of 336 subjects participated in an experiment using these methods. In the experiment, participants completed tasks for all methods within a within-subject design, while domain framing (health or monetary) was randomized between subjects. The tasks were identical in structure but differed in framing, except for method (iii), which relies on time trade-off in health state valuation and is hardly adjusted to a monetary version. After completing the time preference tasks, participants answered questions about health behaviors. Measurements were taken at two time points (T1 and T2) with a two-week interval to assess test-retest reliability.
Results: we found that the direct method, non-parametric method and patience auction method yielded similar time preference estimates within each domain, with average AUC values between 0.51 and 0.57. This indicates that most people exhibited positive time preferences, bhough a significant proportion (20%-48%) showed negative time preferences, particularly with the non-parametric method. The predictive validity of time preferences on health behaviors was limited. There was no consensus on the magnitude of time preferences between the health and monetary domains across methods. Test-retest reliability was relatively low for the direct method, non-parametric method, and patience auctions, whereas the monetary choice questionnaire demonstrated good reliability.
Discussion: Evaluating the feasibility of measuring time preference with different methods is challenging. Different measures, in general, yield relatively similar conclusions about discounting. However, the internal validity of the selected methods was poor. Comparing time preferences across health and monetary domains also offered little insight. Extending non-health time preference measurement methods to the health domain did not reveal significant differences in time preferences between the monetary and health domains. Besides, these time preference measures demonstrated limited applicability for predicting health behaviors.
Adolescent alcohol consumption did not additionally decrease after the minimum legal drinking age was raised (The article is in Dutch, "Alcoholconsumptie jongeren niet extra afgenomen na verhoging minimumleeftijd") (with Elisa de Weerd, Hans van Kipperluis & Ruud Roodbeen) [Link]
ESB Economisch Statistische Berichten, 109 (4839), 491-493.