Abstract for the Population Association of America (PAA) 2007 Annual Meeting

Transcription

1 Birh Replacemen Raios in Europe: A New Look a Period Replacemen Absrac for he Populaion Associaion of America (PAA) 2007 Annual Meeing Topic 1: Feriliy, Family Planning, and Reproducive Healh Session: 111 Low Feriliy in Comparaive Perspecive Auhors: José Anonio Orega and Luis Albero del Rey Universidad de Salamanca Corresponding auhor: José Anonio Orega Dep. de Economía e Hisoria Económica Edificio FES, Campus Unamuno Universidad de Salamanca Salamanca, Spain jaorega@usal.es Fax: Phone: (Ex. 3158) Shor Absrac European reproducion rends are raced using a new period replacemen indicaor: he Birh Replacemen Raio (BRR). The BRR is a replacemen raio ha compares he period number of birhs o he mean size of he mohers generaion a birh. In conras wih he Ne Reproducion Raio, differences beween he Toal Feriliy Rae () and he BRR are no due only o period moraliy. They also incorporae he effec of mohers emigraion and immigraion. The applicaion o a number of European counries beween 1800 and 2004 (depending on daa) shows ineresing conrass beween he and he BRR which race he demographic hisory of he respecive counries. BRR makes i possible o rack he impac of emigraion and immigraion on populaion replacemen over he demographic ransiion and compare he differences beween sending and receiving counries. 1

2 Exended Absrac Moivaion Sandard demographic exbooks indicae ha he Toal Feriliy Rae is a measure of period feriliy, whereas he Ne Reproducion Raio, which akes ino accoun he moraliy of he poenial mohers wihin a synheic cohor, is a measure of reproducion. There are several limiaions o he as a measure of reproducion: (a) The synheic cohor naure of he calculaions makes more difficul is inerpreaion. In general here is an insisence in i being an index of poenial rends, bu here is no clear meaning o ha, (b) In a low moraliy seing, he difference beween he and he (or raher he female sex raio a birh imes he ) becomes less imporan, and he is generally used as a replacemen indicaor, (c) The does no ake ino accoun migraion. This is paricularly undesirable in a conex like he European, where he small raes of naural growh have ofen made migraion he main componen of populaion growh. Remedies o some of hese limiaions have been proposed. For insance, Calo and Sardon (2001) propose replacemen indicaors ha ackle migraion wihin a synheic cohor framework. The problem is again he difficul inerpreaion of he indicaor, and is parial irrelevance, since hey are bes seen as condiional measures for alernaive migraion scenarios. Mehods Our proposal, he birh replacemen raio, ackles boh limiaions simulaneously while providing a naural generalizaion of he o he sudy of replacemen. I is well known ha he can be inerpreed as he raio of he number of birhs, B, o he mean size of he moher s generaion, G, where G can be seen as a weighed average of he female populaion using feriliy raes as weighs (Calo, 1994): G = B / = [ F x () / () ] E x () where x refers o age, o period, and E x o female populaion exposure. Our proposal is o esimae a relaed mean size of he mohers generaion a birh, BG, given by: BG = [ F x () / () ] B f (-x) where B f (-x) is he number of female birhs in period -x. The BRR is herefore defined as: BRR = B / BG In conras o he, he BRR differs from he due o all he componens of populaion change, no merely moraliy. The impac of moraliy, feriliy and migraion on he BRR comes from he relaion: 2

3 Coh BRR = l (1 + k NeMig where l Coh is he average cohor survival and k NeMig is he ne migraion facor. In paricular, moraliy leads o G being lower han BG in a closed populaion. Oumigraion also leads o a reducion of G, while inmigraion leads o increasing G and, herefore, increasing BRR. Also in conras o he, i is a period indicaor of replacemen ha ells us abou he recen demographic hisory of he counry, no abou any poenial growh in he fuure. I is no a synheic cohor measure. This makes i easier o inerpre. The BRR can also be seen as an improvemen over he as a measure of period replacemen (Calo, 2001). Whereas in he he elemens of comparison are differen (birhs in he denominaor and number of mohers in he numeraor), he BRR compares birhs o birhs (see figure 1). Given ha he is currenly he mos widely used measure of period feriliy, we define he BRR using all birhs. A Ne Birh Replacemen Raio (NBRR) can be defined by muliplying he NBRR and he female sex raio a birh 1. The BRR can also be decomposed in is feriliy, moraliy, ou-migraion and immigraion componens. In paricular, in a closed populaion G would be given by: G Mor = 0.5 [ L x ( x) + L x+1 ( x)] B f ( x) where L x () refers o he number of years lived a age x in he female cohor life able for women born in year. By comparing G Mor and G we can ne ou he effec of moraliy on he BRR from hose of ne migraion (k NeMig ). Anoher useful measure is he Equivalen Toal Feriliy Rae (E) an inermediae index beween BRR and E = (1 + k ) BRR = E l NeMig E ells us how big he ough o have been in order o produce he same number of birhs as had been observed, if he populaion had no ne migraion Daa We esimae he BRR and he oher index (observed wheher all informaion is available or esimaed when here is missing informaion regarding feriliy age-schedules and average cohor moraliy) for a number of European populaions as far back as possible, providing also a decomposiion of he effecs of moraliy and migraion. ) 1 We will no pursue ha comparison here. We refer o a companion paper, Orega (2006), where i is shown ha he NBRR and he are approximaely he same in a closed sable populaion. 3

4 In he esimaed index he assumpion are: Feriliy age-schedules: Use of a period-specific schedule compued from available informaion for oher counries. Cohor moraliy: Use of a counry-specific model o combine he informaion available from oher counries wih counry-specific rends We use he following daa sources: Feriliy rae by ages (age reached during he year) and Toal Feriliy Rae. Daabase: Populaion and Social Condiion (EUROSTAT). Inernaional Saisics Yearbook (ISY), 2004, and Naional Agencies. Birhs by year and female cohor life ables. The Human Moraliy Daabase (HMD). Universiy of California, Berkeley (USA), and Max Planck Insiue for Demographic Research (Germany). Available a or and Naional Agencies. Resuls In figures 2 o 5 we can observe for Sweden, Swizerland, Ialy and France he differences beween BRR and, and NBRR and. The BRR and NBRR and he oher index are ake ino accoun he migraion effec and he cohor moraliy while he ohers index do no consider he migraion effec and are affeced by period moraliy. In he pas cenuries, differences beween cohor and period moraliy is a facor ha explain he gap beween and BRR and specially beween and NBRR. Bu also BRR and NBRR are affeced by migraion. BRR appears very sensible o ne migraion: in Sweden a negaive migraion effec beween 1850 and 1950 means BRR below and he opposie when here is a posiive effec beween 1950 and In Swizerland is even mos eviden he effec of migraion o explain he relaion beween and BRR. Ialy and France are good examples of differen rends a relaion beween TRF and BRR due o differen effec of migraion unil recen years. In figure 6 we show he rends in he and he BRR in eleven European counries. Only in some counries where ne migraion has no been very inense he relaionship beween and BRR is similar o ha beween GRR and : he BRR is slighly lower due o moraliy, wih differences becoming less imporan over ime. In counries ha have experienced imporan migraion flows, difference beween he and he BRR can be large. Spain and Ialy in he 1960s are examples where he large oumigraion o oher European counries mean ha he replacemen of generaions was much lower han ha indicaed by he. Noe, for insance, how Ialy s generaions were below replacemen almos all over he period due o large emigraion. In conras, in receiving counries he number of birhs provide a larger replacemen raio ha ha indicaed by he. The case of Swizerland is paricularly appealing: birh replacemen was consisenly higher han he due o a consan ne immigraion of poenial moher s. The BRR was even higher han hree during he1960s. Counries 4

5 where migraion flows have changed he sign over he period provide an ineresing conras. In many of hose counries here is a crossover of he BRR and he as immigraion becomes more imporan. We see insances of his in many counries, like Sweden, France, he Neherlands or Denmark. I is also ineresing o noe ha Spain or Ialy, recipiens of recen large migraion flows, are experiencing such a crossover jus around he year References Calo, G. (1984) Une noion inéressane: L effecif moyen des generaions soumises au risque. I. Présenaion méhodologique. Populaion, 39(6): Calo, G. (2001) Pourquoi la noion de remplacemen ransversal es essenielle, Populaion 56(3): Calo, G and Sardon, J-P (2001) Fécondié, reproducion e remplacemen. Populaion 56(3): Orega, J. A. (2006): Birh replacemen raios: New Measures of Period Populaion Replacemen, FUNCAS working paper / documeno de rabajo 261. Available a hp:// Figure 1: Reproducion index in a Lexis diagram age 50 G age age 15 BRR BG B Year ime 5

6 Figure 2. Sweden : A) BRR,, E ( and ); B) NBRR and ( and ); C) KNeMig, Lcoh and Lper ( and ) BRR E NBRR KNeMig Lcoh Lper Figure 3. Swizerland A) BRR,, E ( and ); B) NBRR and ( and ); C) KNeMig, Lcoh and Lper ( and ) BRR E NBRR KNeMig Lcoh Lper

7 Figure 4. Ialy : A) BRR,, E ( and ); B) NBRR and ( and ); C) KNeMig, Lcoh and Lper ( and ) BRR E NBRR KNeMig Lcoh Lper Figure 5. France : A) BRR,, E ( and ); B) NBRR and ( and ); C) KNeMig, Lcoh and Lper ( and ) E NBRR KNeMig Lcoh Lper

8 Figure 6., BRR and K NeMig in welve European counries Norw ay Sw eden Denmark Finland Ialy Spain Ausria Sw izerland England&Wales France Belgium Neherlands Norw ay Sw eden Denmark Finland Ialy Spain Ausria Sw izerland BRR BRR BRR England&Wales France Belgium Neherlands Norw ay Sw eden Denmark Finland Sw izerland Ausria Spain Ialy K NeMig K NeMig K NeMig England&Wales France Belgium Neherlands 8