Mortality and fertility data play an important role in policy making and planning. But in various countries of the developing world such data are limited and unreliable. Lack of continuous registration system is one of the main reasons behind it. This book not only gives a detailed theoretical background of several existing methods used in correction and analysis of such data but it also discusses about some new methodologies especially developed for the data of such countries. The role of several agencies in data collection is discussed in detail. Model developed for predicting mortality and fertility for countries with accurate data is tested on data of the developing world. The accuracy of the data is mathematically estimated through various methods. This is based on mortality and fertility data from Nepal and India which serve as examples from the developing world. This book will be useful to graduate, post graduate students and researchers specializing in mathematical demography, data analysis and statistics.