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Youssouf Camara is the winner of the Economics thesis prize awarded by the Institut Polytechnique de Paris (thesis supervisor: David Bounie), as well as the 2023 thesis prize awarded by the Association Francophone de Recherche en Economie Numérique.
The thesis is intituled: 'Four essays on empirical economics in the era of high-frequency data'.
This thesis uses card payment transaction data known as high-frequency data to identify the causal effects of technological innovations and the COVID-19 pandemic. The first chapter assesses the causal impact of recent disruptive innovations in digital payments, specifically, the contactless payment card. We show that the introduction of contactless payment technology significantly affects the economic activity of businesses that adopt this technology compared to those that do not, notably through spillover effects. The effects are particularly strong for small and new businesses, and show the real impact of technological innovations. The second chapter explores the role of digital payment technologies in mitigating the impact of shocks through improving business resilience. The results indicate that businesses with the latest digital payment technology were more resilient to COVID-19 shocks than those not yet using it. They also show that accepting contactless payments during an epidemic shock helps businesses acquire more new customers. Like the first chapter, we argue that digital payment technology continues to support sales growth and accelerates the substitution between digital and non-digital payments. In the third chapter, we estimate the impact of COVID-19 on consumer mobility and spending. We also examine the role of online commerce in the rapid recovery of business activity when an economy is hit by an unexpected shock that paralyzes offline activity. We show that public health measures to limit the spread of the COVID-19 epidemic sharply reduced consumer mobility and spending by more than half. Concerning the decline in spending, we find that it is about twice as large as the decline in online spending. Sector-level analyses highlight the key role of online commerce in filling gaps and making the economy more resilient in the event of total off-line retail closure. The last chapter focuses on the analysis of spatial consumption behavior and the impact of online trade development on regional trade linkages. It shows that online transactions, in addition to occurring more frequently outside the consumer's home region, are more concentrated in already developed regions. The development of online commerce has increased the concentration of overall economic activity and may have important implications for regional economic development.
