The selection of climate policies should be an exercise in risk management reflecting the many relevant sources of uncertainty. Studies of climate change and its impacts rarely yield consensus on the distribution of exposure, vulnerability, or possible outcomes. Hence policy analysis cannot...

The selection of climate policies should be an exercise in risk management reflecting the many relevant sources of uncertainty. Studies of climate change and its impacts rarely yield consensus on the distribution of exposure, vulnerability, or possible outcomes. Hence policy analysis cannot...

Social distancing via shelter-in-place strategies has emerged as the most effective way to combat Covid-19. In the United States, choices about such policies are made by individual states. Here we show that the policy choice made by one state influences the incentives that other states face to...

There are many social situations in which the actions of different agents reinforce each other. These include network effects and the threshold models used by sociologists (Granovetter, Watts) as well as Leibenstein's "bandwagon effects." We model such situations as a game with increasing...

We model tipping as a game-theoretic phenomenon and investigate the connection between supermodular games, tipping of equilibria and cascading, and apply the results to issues that arise in the context of homeland security and computer security. We show that tipping and cascading can occur in...

In an interdependent world the risks faced by any one agent depend not only on its choices but also on those of all others. Expectations about others' choices will influence investments in risk-management, and the outcome can be sub-optimal investment all round. We model this as the Nash...

This paper extends our earlier analysis of interdependent security issues to a general class of problems involving discrete interdependent risks with heterogeneous agents. There is a threat of an event that can only happen once, and the risk depends on actions taken by others. Any agent's...

Do firms have adequate incentives to invest in anti-terrorism mechanisms? This paper develops a framework for addressing this issue when the security choices by one agent affect the risks faced by others. We utilize the airline security problem to illustrate how the incentive by one airline to...