Tfr

This study offers a method for removing the effects of tempo distortions from the total fertility rate (TFR). The aim is to advance understanding of the level and trend of past fertility for generating better projections. Correcting for period effects is important due to the heavy reliance on TFR as a demographic measure. TFR is an average of the number of births a woman would have during her reproductive years (ages 15-49 years). TFR should reflect the changes in the timing of childbearing, the relationships between period and cohort measures, the nature and validity of period measures, and the extent to which fertility should include controls for age, parity, duration of marriage, or other demographic factors. Life table measures that standardize for parity or duration in parity do not address the distortions of changes in the timing of childbearing. A decline in the cohort size leads to changes in the mean age of childbearing that do not represent true tempo effects. The proposed method assumes fertility changes by period, duration since last birth, parity, and age, but not by cohort. It is calculated by dividing the observed TFR at each birth order by 1 minus the change in mean age at childbearing at order "i" during the year. Situations include where only births of order one occur, all women in every birth cohort have their first births at a single exact age, all births occur at equal intervals during the year, and all cohorts have the same number of women. The model is tested for the US and Taiwan. The method adjusts for the later age at childbearing and reveals close to replacement fertility in the 1970s and 1980s in the US.

Temporary Flight Restrictions (TFRs) can be implemented for several reasons, including security, hazards, space operations, special events, and VIP travel. VIP TFRs, specifically presidential TFRs, have much greater impact than other types of TFRs because they encompass a larger geography, are longer in duration, and may have little advance notice. The TRB Airport Cooperative Research Program's ACRP Research Report 224: Understanding Impacts to Airports From Temporary Flight Restrictions identifies financial and other ramifications of TFRs on airports and aviation-related businesses. Also included as part of the report is an electronic tool that will estimate the financial ramifications of a TFR for a specific airport or related business. Further, a video was created that shows how to use the spreadsheet, with instructional voiceovers explaining its features.