Tempo and quantum of fertility in Iran: An Application of the Synthetic Parity Progression Ratio Method

After sharp fall in the 1990s, Iran’s fertility decline slowed down during the 2000s fallen to around replacement level. Following two decades of fertility control policies, more recently, the Iranian Government has been concerned that fertility will fall to a very low level and a draft pronatalist policy has been designed and is being put to the parliament. The concern has been based on estimates that Iran’s current fertility is as low as 1.6, but there are questions about the reliability of estimates of fertility. There is a near-to-complete birth registration system but how near-to-complete is unknown. Own children estimates are possible but they too may not be sufficiently reliable. Furthermore, cross-sectional fertility measures can be confounded by changes in the timing of births across women's lifetimes (tempo) as well as by changes in the numbers of children that they have by the time they end their childbearing (quantum). When the age-based TFR is used, tempo and quantum can be assessed a long time after the fact by comparing the TFR for real birth cohorts with the cross-sectional or synthetic TFR. The problems involved in assessing tempo and quantum using the age-based TFR can be overcome by using parity progression ratios. The findings suggest that tempo effects evident particularly in the 1990s are no longer evident.