Uses and importance of the models in analyzing real life time data for first birth interval

In this paper, an attempt has been made to explore the uses and importance of the models used to explain the human fertility through real data for the researchers presently working in the field of demography. Generally, the levels and trends of human fertility can be easily obtained from the descriptive study of the real data. But some inherent characteristics of the phenomena, human fertility, are found only by applying the appropriate model to the real demographic dataset. The present paper is mainly focused on the models for first birth interval (FBI) as FBI is one of the important determinants of human fertility. In this study, different models are considered and their parameters are estimated by applying it to the real data of the FBI under the different sampling frames. Here the different sampling frames are taken as different ages at marriage since ages at marriage play a significant role in shaping the length of the FBI. These models are applied to the real data set of different major states of the country obtained from National Family Health Survey III. Through the application of the models proposed, different inherent characteristics of human fertility are obtained from the estimates of parameters included in the models.