## Article

#### Title: Impact of Heterogeneity on Closed and Open Birth Intervals

##### Issue: Volume 81 Series B Part 2 Year 2019
###### Abstract
Vast literatureis available where modelling for duration between ith and (i+1)th births has been done. Apart from other considerations these models assume that consecutive birth intervals are independently distributed. This assumption may be quite reasonable if the population of females is homogeneous with respect to fertility parameters involved in the model. However, if population is heterogeneous with respect to these parameters, then the consecutive intervals are likely to be dependent. The behaviour of closed and open birth intervals under the condition of heterogeneity in the population with respect to certain fertility parameters is investigated.