Research

Below is a list of my research output organized by field and listed by date.

Agricultural, Environmental, and Health economics

How is climate fuelling the thirst for sweetness? Exploring drivers and adaptation (working paper)

Co-authored with Laure de Preux (Imperial College London).
Link to paper: https://dx.doi.org/10.2139/ssrn.4862789 
Slides: TBA

Amid the current syndemic of obesity and climate change, little is known about the effect of extreme temperatures on dietary behaviour. Using exogenous daily variations in weather and a nationally representative consumer panel in the U.S., we find that extreme heat increases the volume purchased of sugary drinks, with persistent impacts even after accounting for inter-temporal purchase shifts. We explore heterogeneous effects and a range of potential drivers, including changes in shopping habits, inter-channel substitutions, retailers' price adjustments, and psychological biases. Results reveal higher impacts among the most vulnerable households and no evidence of long-run adaptation by historical heat exposure. We combine our estimates with output from climate models for 2080-2099. Our projections indicate that climate change may increase sugary drink purchases.

Seminar presentations: Imperial College London (Economics & Public Policy)
Conference presentations: European Association of Environmental and Resource Economists (EAERE 2024); European Health Economics Association (EuHEA 2024); French Economics Association (AFSE 2024); Association of Environmental and Resource Economists (AERE 2024); Canadian Economics Association (CEA 2024); Maastricht Workshop on Applied Economics of the Environment (MAEE 2024)

Can differentiated value-added tax rates promote healthier diets? The case of Costa Rica (submitted)

Solo-authored.
Slides: TBA

In February 2023, Costa Rica reformed its basic value-added tax basket attracting a reduced rate with the aim to promote more balanced diets. This paper assesses ex-ante the impact of the reform on nutrient availability and household spending across income groups. Price elasticities are estimated using pooled National Household Income and Expenditure Survey data and a two-step censored quadratic almost ideal demand system model accounting for price and total expenditure endogeneity. Nutritional information is derived from food composition tables. Food items are grouped by processing level as a proxy to explore differences in own- and cross-price effects between healthier and less healthy items.  

Seminar presentations: University of Birmingham (Centre for the Economics of Obesity); University of Costa Rica (School of Nutrition); Imperial College London (Centre for Health Economics & Policy Innovation; Public Health Policy Evaluation Unit)
Conference presentations: Quantitative Methods in Social Sciences conference (University of Warwick, 2023)

Public policy and public health

Taxation of foods high in saturated fats, sodium, and sugars in India: A modelling study of health and distributional equity impacts (work in progress)

Co-authored with Jingmin Zhu (Imperial College London), James Turner (Imperial College London), Jack Olney (Imperial College London), William Joe (IEG, New Delhi), Manika Sharma (RTSL, New Delhi), Lindsay Steele (RTSL, New York), and Franco Sassi (Imperial College London)

The consumption of energy-dense foods and foods high in saturated fats, sodium, and sugars (HFSS) is increasing in India, as well as overweight and obesity. At the same time, a significant portion of the poor still cannot afford a recommended healthy diet. This study aims to assess the effect of fiscal policy scenarios to promote healthier diets on the distribution of household expenditure, nutrient availability, and health outcomes. Own- and cross-price elasticities are estimated using the National Sample Survey Office Household Consumer Expenditure survey 2011-2012 and a quadratic almost ideal demand system model accounting for potential sources of endogeneity. Baseline nutrient availability is derived from Food Composition Tables and purchased quantities are adjusted to December 2022 using the Centre for Monitoring Indian Economy’s Consumer Pyramid data and detailed consumer price index trends. We assess various Goods and Services Tax (GST) scenarios using nutrient profile modelling to differentiate tax rates. We estimate the distributional impact of each scenario on household expenditure and per capita nutrient availability as well as national GST revenue. Finally, we evaluate the impact on diet-related diseases and associated healthcare expenditure using the Health-GPS microsimulation model calibrated with national health survey microdata and estimates from the Institute for Health Metrics and Evaluation. 

Seminar presentations: Institute for Economic Growth (New Delhi, 2023)
Conference presentations: Delivering for Nutrition in South Asia (IFPRI, Kathmandu, Nepal, 2023)

Comparing taxes on alcoholic beverages in the Region of the Americas (Addiction, 2023, doi:10.1111/add.16146)

Co-authored with Rosa Carolina Sandoval (PAHO) and Maristela G. Monteiro (PAHO).

Background and Aims: Excise taxes represent one of the most cost-effective policies to reduce the harmful use of alcohol. Existing information about their design is limited and no standardized metric has been used to compare tax levels in the Region of the Americas. This study aimed to compare alcohol excise tax policies throughout the Americas, compare tax levels and consider opportunities to improve the impact of excise taxes on alcohol consumption and health.
Design and Setting: Descriptive analysis using a method developed by the Pan American Health Organization and adapted from the World Health Organization's tobacco tax monitoring. Data were collected by surveying ministries of finance and reviewing tax legislation in effect as of November 2020 in the Region of the Americas.
Measurements: Tax policy design indicators, taxes as a percentage of the retail price of the most-sold brand of beer, wine and spirits, including a weighted average indicator across beverage types, and tax levels per standard drink (10 g ethanol) in international dollars at purchasing power parity.
Findings: Thirty-three countries in the Americas (94%) apply excise taxes on alcoholic beverages, with Argentina and Uruguay not applying them to wine. There is significant heterogeneity in excise tax design across countries and beverage types. Only a third of amount-specific excise taxes are regularly adjusted to avoid erosion. Regional median excise taxes represent the highest share of the price for spirits (21.4%) and the lowest for wine (11.0%). The regional median consumption-weighted average excise tax share across all beverage types is 12.0%. Excise tax shares are generally higher in Latin America than in the Caribbean and Canada. Excise tax levels per standard drink are generally lower for spirits than for other beverages.
Conclusions: Alcohol excise tax policies vary significantly across the Americas, often reflecting national consumption patterns. To maximize their public health impact, tax rates could be increased and tax designs improved, particularly to ensure higher tax burdens on high-strength drinks.

Conference presentations: Alcohol Policy 19 (2022)

Comparing taxes as a percentage of sugar-sweetened beverage prices in Latin America and the Caribbean (The Lancet Region Health - Americas, 2022, doi:10.1016/j.lana.2022.100257)

Co-authored with Miriam Alvarado (University of Cambridge), Rosa Carolina Sandoval (PAHO), Fabio da Silva Gomes (PAHO), and Guillermo Paraje (Universidad Adolfo Ibanez).

Background: Excise taxes can be used to reduce the consumption of sugar-sweetened beverages (SSBs), an important preventable risk factor for noncommunicable diseases. This study aimed to compare novel standardized indicators of the level of taxes applied on SSBs as a percentage of the price across beverage categories in Latin America and the Caribbean.

Methods: We used a method developed by the Pan American Health Organization and adapted from the World Health Organization's tobacco tax share. The analysis focused on the most sold brand of five categories of non-alcoholic beverages. Data were collected by surveying ministries of finance and reviewing tax legislation in effect as of March 2019.

Findings: Of the 27 countries analyzed, 17 applied excise taxes on SSBs. Of these, median excise taxes represented the highest share of the price for large sugar-sweetened carbonated drinks (6·5%) and the lowest for energy drinks (2·3%). In countries where excise taxes were applied on bottled waters, tax incidence exceeded the one applied on most SSBs. Overall, excise tax shares were higher in Latin America than in the Caribbean. Including all other indirect taxes (e.g., value added tax), median total tax shares were between 12·8% and 17·5%. At least two countries earmarked part of SSB excise tax revenues for health purposes.

Interpretation: Excise tax levels are generally low in the region. From a public health perspective, tax rates could be increased, and tax designs improved (e.g., excluding bottled waters). The method describe here provides a feasible and informative way to monitor SSB taxation and could be replicated in other regions and over time.

Seminar presentations: PAHO (2022, link)