Designing a good unemployment insurance scheme is a delicate matter. In a system with no or little insurance, households may be subject to a high income risk, whereas excessively generous unemployment insurance systems are known to lead to high unemployment rates and are costly both from a fiscal perspective and for society as a whole. Andreas Pollak investigates what an optimal unemployment insurance system would look like, i.e. a system that constitutes the best possible compromise between income security and incentives to work. Using theoretical economic models and complex numerical simulations, he studies the effects of benefit levels and payment durations on unemployment and welfare. As the models allow for considerable heterogeneity of households, including a history-dependent labor productivity, it is possible to analyze how certain policies affect individuals in a specific age, wealth or skill group. The most important aspect of an unemployment insurance system turns out to be the benefits paid to the long-term unemployed. If this parameter is chosen too high, a large number of households may get caught in a long spell of unemployment with little chance of finding work again. Based on the predictions in these models, the so-called "Hartz IV" labor market reform recently adopted in Germany should have highly favorable effects on the unemployment rates and welfare in the long run.

I use three decades of county-level data to estimate the effects of federal unemployment benefit extensions on economic activity. To overcome the reverse causality coming from the fact that benefit extensions are a function of state unemployment rates, I only use the within-state variation in outcomes to identify treatment effects. Identification rests on a differences-in-differences approach which exploits heterogeneity in county exposure to policy changes. To distinguish demand and supply-side channels, I estimate the model separately for tradable and non-tradable sectors. Finally I use benefit extensions as an instrument to estimate local fiscal multipliers of unemployment benefit transfers. I find (i) that the overall impact of benefit extensions on activity is positive, pointing to strong demand effects; (ii) that, even in tradable sectors, there are no negative supply-side effects from work disincentives; and (iii) a fiscal multiplier estimate of 1.92, similar to estimates in the literature for other types of spending.

This study explores the prospect of the application of the basic principles of ICL into many other potential areas of social and economic policy. Using case studies it evaluates previously implemented ICL schemes where interest rate subsidies are usually the norm, and questions the merits of this approach.