This paper provides an overview and synthesis of the literatures analysing games where players are connected via a network structure. While it focuses on the game theoretic modeling, it also also include some discussion of analyses of peer effects, as well as applications to diffusion, employment, crime, industrial organisation, and education.

How to reduce incarceration rates without fuelling a crime boom? This column argues that by being more selective over whom to lock up and for how long, scarce public funds can be put to better use.

How to save the banks but not the bankers? This column argues that fines for criminal behaviour in banks are not enough – it may be time to start locking people up.

If it were a business, the Mafia would be one of Italy’s most successful and one of the largest in Europe. But how did it come to be so powerful? This column argues that it began with control of the international lemon trade in the 19th century.

Can organised crime divert public spending? This column presents evidence of the Mafia influencing public transfers and argues that geographically targeted aid should take into account the risk that at least part of the funding feeds into organised crime.

How should society fight crime? This column argues education policy should be part of the answer. Exploiting a Swedish education reform as a source of exogenous variation in years of education, it suggests that one additional year of schooling decreases the likelihood of conviction by 7.5% for males and by 11% for females.

According to the famous White House saying, policymakers should never let a crisis go to waste. This column argues that economists shouldn’t do so either. Instead of cursing about cuts in research funding, they should look at cheaper ways to evaluate policy – perhaps through mechanism experiments.

Given recent budget problems around the world, many governments have proposed sharp cuts to education. What are the likely long-run costs of these cuts? This column reviews a growing body of studies and concludes that crime rates are likely to increase, health and mortality are likely to deteriorate, and political and social institutions may suffer.

In the US, more people work in private security than in all police forces combined, yet public debate about crime prevention typically looks at the use of public resources to deter, incapacitate, or rehabilitate criminals. This column calls for more discussion of how private action can make policing more effective and reduce the profitability of crime. One such experiment – “business improvement districts” in Los Angeles – has generated remarkable social benefits.

Potential victims often ward off crime by taking appropriate precautions. This column argues that government policy targeted at strengthening the precautionary response of potential victims can make a big difference. It shows that mandating the installation of burglar-resistant features in residential construction in the Netherlands reduced burglary risk by 26%.