Reducing the use of chemical pesticides is a key objective in many countries. Yet environmental friendly alternatives usually differ from pesticides in terms of both cost and efficiency, whereas the spreading patterns of pests and diseases make farmer adoption dependent on neighbors' strategies. Focusing on a vector-borne epidemic disease affecting perennial crops, we study the profit maximizing strategies of two producers facing an epidemic. On the one hand, using pesticides stops the spatial spread of the disease at both a private and an environmental cost. On the other hand, depending on the chosen level of monitoring, removing the diseased plants slows down contagion but never results in full eradication either. Using a stylized 3-period framework, we investigate the conditions under which full monitoring arises as a stationary equilibrium, and the implications for public regulation when both environmental externalities and aggregate profit enter in the regulator's objective.
I examine the trade-off of the scientist who has access to citizen science (CS) or traditional science (TS) to undertake her research. A sequence of projects are successively available on a discrete time horizon. Each project is a public good with some value. For each project, a scientist (she) chooses to implement it with CS or TS. With TS, she implements the project for sure but it takes one period. With CS, the project is implemented immediately with the help of two citizens. However, its success is uncertain and depends on the citizens' actions. When the successive projects have the same value, the scientist's strategy is a cut-off: when the value of the project is above some threshold, she uses CS. Below this threshold, she uses TS. This result is generalized to any sequence of project values which satisfies the Markov property. In an extension, two scientists compete to attract citizens on their project. Focusing on stationnary Markovian equilibria, I show that the equilibrium in pure strategies is unique: for sufficiently high project values, both scientists always choose CS. For sufficiently low values, both scientists always choose TS. In both cases, there exist no equilibrium in mixed strategies. For intermediate project values, the unique equilibrium is in mixed strategies: if one scientist is stuck with choosing TS at the former period, the other one always chooses CS. Otherwise, they both mix between TS and CS.
Citizen Science, Platforms, and Project Implementation, with Jean-Marc Zogheib
We examine the impact of citizen science on the digital economy by investigating the incentives of citizens, scientists, and digital platforms to implement a scientific project. We build a simple model where a two-sided platform supplies citizen science services to two scientists on one side, and two citizens on the other side. Project implementation brings a social value benefiting each project contributor. A scientist decides between project implementation via the platform and an outside option. A project may be implemented with some probability depending on citizens' attention devoted to the project. If the platform is benevolent, we find three possible scenarios of project implementation depending on the social value of a project, the probability of implementation, and the opportunity cost of citizen science. Later on, we will refine the framework and solve the case of a commercial platform.
I study the trade-off of the scientist who chooses between citizen science (CS) and traditional science (TS) for her research. After time 0, there exists an new idea which can be studied. Two scientists can discover this idea at any time. Their objective is to publish it before the other does. However, competition is only potential as a scientist's discovery time is not observable by her competitor. At the scientist's discovery time, she faces two technological choices, which are not available past that time. The first one is TS: she takes time to let the idea mature. There exists an optimal maturation delay which maximizes her publication payoff with TS without any competitor. With the second choice, called CS, the scientist involves citizens' help to publish instantaneously the idea. However, she incurs a fixed cost to make the idea available to citizens. Moreover, the latters are non-experts so there is some risk error that the publication is of bad quality, which brings her no payoff. Focusing on Bayesian pure-strategy equilibria, I prove that there exists two kinds of symmetric stationary equilibria. When CS is low-cost, every scientist chooses CS. Otherwise, everyone chooses TS. Besides, I study equilibria in which every scientist chooses TS before a discovery time threshold and CS after. There exists no such equilibrium when it satisfies one of these two assumptions: i) the threshold discovery time is lower than the equilibrium publication time of the scientist discovering the idea at time $0$ and ii) the equilibrium scientists' strategy is continuous at the threshold discovery time. At last, there exists no asymmetric equilibrium in which scientists choose different technological choices.