Crises

In demography much scientific effort is invested to study the continuous. We have a whole range of statistical techniques to describe, analyze, and predict ongoing trends in fertility, mortality, and migration. Actually, it is the quintessence of population projection methods, life tables techniques and synthetic rates (such as the Total Fertility Rate, the Net Reproduction Rate, etc.) to assume continuity or at least a steady change. In reality, however, the world is not a tranquil flow of events. One might say that crises are a constituency of our existence. Sometimes they affect a whole population, sometimes a small group or an individual, in a few cases they might even endanger the existence of mankind