The fact that Stephan Klasen can always give a precise answer to very complicated or even complex questions inspired the idea for this book. We asked 50 development economists (and friends of Stephan) around the world to answer 50 (serious and not-so serious) questions about development research...

Using household survey data from 40 developing countries, we estimate the mortality impact of improved water and sanitation access. We find that the average mortality reduction achievable by investment in water and sanitation infrastructure is 8 and 22 deaths per 1000 children born for basic and...

Continued population growth and increasing urbanization have led to the formation of large informal urban settlements in many developing countries in recent decades. The high prevalence of poverty, overcrowding, and poor sanitation observed in these settlements—commonly referred to as...

High urban mortality delayed transitions to low mortality in 19th century Europe, but an urban mortality advantage emerged as European transitions progressed into the 20th century. Recent analysis has suggested that high mortality in the rapidly growing urban slums of developing countries might...

For more than a hundred years, advances in development were associated with decreasing fertility rates. This led to total fertility rates far below replacement level in most developed countries. However, during the last decade fertility rates started to increase again in various developed...