Published articles

Compensate at your own risk: Heterogeneity in compliance with preventive behaviors through the lens of economic and social preferences - A. Lacombe and M. Guillon (2026) - Accepted for publication in the International Journal of Health Economics and Management

Protective behaviors are crucial for controlling the spread of infectious diseases. Until now, most of the literature on the understanding of the willingness to comply with protective behaviors at the individual level focused on either one of those behaviors or studied several behaviors but independently. However, protective behaviors might not be independent of each other’s and the question of the relationship between these various behaviors deserves to be further investigated. The COVID-19 pandemic represents an interesting setting to study compliance with preventive behaviors when several prophylactic measures aiming to reduce the same infection risk are available. The aim of this study is to investigate how economic and social preferences may shape the relationship between three types of COVID-19 protective behaviors among a representative sample of the French population: 1) respect of restrictions on movement, 2) compliance with barrier gestures and 3) COVID-19 testing. Using a Latent Class Analysis, we identify four groups of individuals with diverging patterns of compliance with protective behaviors, differing both in terms of intensity and types of prophylactic measures followed: individuals who apply all protective behaviors, those who reject them all, individuals who do not respect restrictions on movement but still protect themselves and others by applying barrier gestures, and those who do not use barrier gestures but comply to movement restrictions. Our results support the existence of a risk compensation process leading some individuals to tailor their menu of prophylactic measures until they reach the risk threshold they are willing to handle. The composition of the menu of prophylactic measures appears to be linked with individuals’ economic and social preferences including risk and time preferences, prosociality, and interpersonal trust. Exploring heterogeneity in preventive behaviors may motivate authorities to design targeted prevention and communication campaigns that are better tailored to achieve public health goals. 

Does improving diagnostic accuracy increase artificial intelligence adoption? A public acceptance survey using randomized scenarios of diagnostic methods - Y. Hswen, I. Rafaï, A. Lacombe, B. Davin-Casalena, D. Dubois, T. Blayac, B. Ventelou (2024) - Published in Artifical Intelligence in Health

This study examines the acceptance of artificial intelligence (AI)-based diagnostic alternatives compared to traditional biological testing through a randomized scenario experiment in the domain of neurodegenerative diseases (NDs). A total of 3225 pairwise choices of ND risk-prediction tools were offered to participants, with 1482 choices comparing AI with the biological saliva test and 1743 comparing AI+ with the saliva test (with AI+ using digital consumer data, in addition to electronic medical data). Overall, only 36.68% of responses showed preferences for AI/AI+ alternatives. Stratified by AI sensitivity levels, acceptance rates for AI/AI+ were 35.04% at 60% sensitivity and 31.63% at 70% sensitivity, and increased markedly to 48.68% at 95% sensitivity (p< 0.01). Similarly, acceptance rates by specificity were 29.68%, 28.18%, and 44.24% at 60%, 70%, and 95% specificity, respectively (P< 0.01). Notably, AI consistently garnered higher acceptance rates (45.82%) than AI+(28.92%) at comparable sensitivity and specificity levels, except at 60% sensitivity, where no significant difference was observed. These results highlight the nuanced preferences for AI diagnostics, with higher sensitivity and specificity significantly driving acceptance of AI diagnostics. 

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Working papers

Diagnostic Test Value: How Treatability and Transmissibility interact with individual traits - A. Lacombe

Diagnostic tests have become a cornerstone of early disease detection, playing a crucial role in curbing the spread of infectious diseases and enhancing the management of non-infectious conditions. Nonetheless, testing rates remain below public health objectives. This paper focus on the individual’s decision to undergo testing. Using a representative sample of the French population, we examine how two disease features, its treatability and transmissibility, and personal characteristics shape people’s willingness to get tested and the hedonic value they assign to diagnostic information for a hypothetical disease. Repeated elicitation of willingness to pay while making diseases characteristics vary enables the estimation of within individual variation in diagnostic valuation. We employ an interval-censored regression model with endogenous selection correction and correlated individual-specific random intercept to accurately capture individuals’ choices to undergo testing and their monetary assessment of its worth, serving as an indicator of their underlying utility. We find that both transmissibility and treatability shape test-seeking behaviour, with substantial heterogeneity across individuals. In particular, risk, time, and social preferences, together with trust in science, play an important role in the decision-making process. These findings inform strategies to increase participation in screening programmes and improve public-health outcomes by distinguishing traits linked to a general propensity to test from those that make individuals especially responsive to treatability or transmissibility.

Preferences for comprehensive HIV prevention services among women and girls in Nairobi and Kampala: a discrete choice experiment - UPTAKE research team

Climate-Informed Resource Allocation for Infectious Disease Prevention: A Spatial Economic Evaluation - A. Lacombe

Ongoing projects

ACME: Improving the acceptability and accessibility of preventive countermeasures, including vaccines, in emerging epidemics - Principal investigator: Prof. J. Mueller (EHESP and Institute Pasteur) - Funding: ANRS MIE (PEPR France 2030)

ACME project website

UPTAKE: Universally Accessible HIV Prevention Technologies for African Girls and Young Women through Knowledge Applied from Behavioural Economics - Principal Investigator: Prof. M. Gafos (LSHTM, Department of Global Health and Development)

Peer review

Plos One (2023)

“There’s no such thing as the unknown, only things temporarily hidden, temporarily not understood.”
Cpt James T. Kirk