The Bongaarts-Feeney tempo-adjusted TFR (TFR*) (cont.)

Figure 4 compares the observed TFR, the TFR* and the cohort TFR for American women born in the first half of the 20^th century. In order to facilitate the comparison between period and cohort measures, the period measures are weighted for the years in which the cohort did its childbearing. In that plot, the tempo-adjusted TFR* mimics the fertility trends of the cohorts much better than the period TFR, and that led Bongaarts and Feeney to their assertion that the TFR* is a “period measure purged of tempo effects”. This new measure may thus provide a better estimate of the number of children women will bear under current conditions than the ordinary TFR, and therefore, a better estimate of the fertility quantum.

Figure 3: Observed and estimated completed fertility of cohorts of US women born between 1904 and 1941

Adapted from Bongaarts and Feeney (1998)