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Education and the contemporary ‘baby boom’: Evidence from the Northern Ireland Longitudinal Study. Patrick McGregor Patricia McKee. “Predicting Short Run Changes in Fertility in Northern Ireland”. a project funded by.
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Education and the contemporary ‘baby boom’: Evidence from the Northern Ireland Longitudinal Study Patrick McGregor Patricia McKee “Predicting Short Run Changes in Fertility in Northern Ireland” a project funded by The authors are grateful to the NILS team at NISRA for their assistance
Education and the contemporary ‘baby boom’: Evidence from the Northern Ireland Longitudinal Study • Overview • Education and fertility • The NILS • The data • The statistical model • Results • Conclusion
A baby-boom fuelled by rising fertility rates and immigration has pushed the population of the United Kingdom to more than 61 million for the first time. The Times, 28 August 2009 Overview
Fertility in Northern Ireland Total Births Age Specific Fertility Rates
Education and fertility Static economic analysis Max ST Children assumed to be normal ‘goods’ so: but possibly or possibly not! The home production framework allows the cost of children to be expressed as a function of the parents’ wages and their respective shares in the costs of producing child quality Education and fertility
Dynamic economic analysis The ‘user cost’ of a child now is a function of a sequence of prices such as the female wage rate The optimal profile of a woman’s stock of human capital will be jointly determined with the timing of the births of her children. Any empirical analysis should permit the demographic profile to vary with educational attainment Education and fertility
The NILS • The NILS potential mothers: those women with health card registrations, aged 16-44 years and whose DOB is one of the 104 in the systematic sample • Registrations downloaded biannually and constitute potential panel members • Details of any birth to a NILS mother are forwarded by the GRO to the NILS • 2001 Census: An attempt is made to link the Census details of all NILS mothers The NILS
Population on Census Day, 2001 Total Population Census 1,685,267 (4.84% Imputed) BSO 1,768,473 (4.94% list inflation) Women in NILS aged 16-44 years Census 101,034 ( Census x 104/365.25) BSO 107,874 list inflation 6,840 (6.3%) Expected imputed census records 4,890 (101,034 x 0.0484) Fertility Panel with census records 93,601 BSO – FP 14,273 Mismatch = 14,273 – 6,840 – 4,890 = 2,543 The NILS
Year N % pattern 01 5083 3.5 1000000 01-02 5167 3.6 1100000 01-03 5771 4.0 1110000 01-04 4523 3.1 1111000 01-05 4804 3.3 1111100 01-06 4451 3.1 1111110 01-07 76878 53.0 1111111 02-07 4416 3.1 0111111 03-07 4353 3.0 0011111 04-07 4649 3.2 0001111 05-07 5067 3.5 0000111 06-07 5796 4.0 0000011 07 6504 4.5 0000001 Presence of women in the Fertility Panel:the effect of Age The fertility panel essentially is the 1957 – 77 cohort and ignores the 1978 – 91 cohort due to the absence of educational information The data
GRO 7,019 32,960 Census 01 101 4,653 61,263 26,710 530 Census 91 BSO 24,041 Sources of Information available for the NILS Fertility Panel The data
Sources of Parity in the Fertility Panel Parity from Freq. Percent Census - offspring 116,327 74.0 GRO births 10,141 6.5 91 census 6,432 4.1 Count births 97-01 178 0.1 Census + n of births 158 0.1 Missing 24,041 15.3 Total Women157,277 100.0 The data
Level 0 Level 1 Level 2 Level 3 Level 4 Level 5 No qualifications GCSE grade D-G; 1-4 CSEs grade 1; 1-4 ‘O’ level passes; NVQ level 1 5+ CSEs grade 1; 5+ GCSEs grade A-C; 5+ ‘O’ level passes; NVQ level 2 2+ ‘A’ levels; 4+ AS levels; NVQ level 3 or GNVQ Advanced First degree; NVQ level 4; HNC ; HND Higher degree; NVQ level 5 Educational Qualifications The data
Distribution of Educational Attainment by Year that Woman was aged 24 Source: 2001 Census The data
Women in the Labour Market Source: DETINI The data
Mean Age of Mother at Time of Birth The data
The Statistical Model • Raftery, AE, Lewis, SM and Aghajanian, A (1995). • Demand or Ideation? Evidence from the Iranian Marital Fertility Decline, Demography, vol. 32. • Data: 1977 Iran Fertility Survey • “ each woman-year of exposure is treated as a separate case” • Five clocks: • Age Period Cohort Parity Duration The Statistical Model
The Logit Model TIME captures the change in quantum for women aged > 23 EDUCATION includes interactions with PARITY, DURATION and TIME so demographic profile can vary with educational attainment The Statistical Model
Logit Regression Results Demographic age 237.053 age2 -309.685 age3 182.198 age4 -41.369 par1 2.078 par2 2.595 par3 2.161 pargt3 0.899 dur1 -3.974 dur2 -2.483 dur3 -1.661 dur4 -1.783 dur5 -1.540 Time yr2002 -0.457 yr2004 -0.427 yr2005 -1.473 yr2006 -0.111 timetrend 0.667 Economic fwage-1 -1.423 factivityrate-1 -0.971 Interest-1 0.244 Other catholic 0.169 constant -2.758 Education level01 constant 0.651 quality -2.003 timetrend -0.173 quality*tt 0.343 Demographic par0 -0.384 par1 -0.386 par2 -0.178 par3 -0.096 dur1 0.046 dur2 -0.234 dur3 -0.195 dur4 -0.091 dur5 -0.140 durgt5 -0.03 Education level 45 constant 1.438 quality -5.470 timetrend -0.145 quality*tt 0.702 interactions par0 -0.010 par1 0.258 par2 0.238 par3 0.094 dur1 0.138 dur2 0.484 dur3 0.468 dur4 0.557 dur5 0.394 durgt5 0.394 Demographic interactions agepar1 -1.420 agepar2 -2.663 agepar3 -2.441 agepargt3 -1.341 agedur1 3.512 agedur2 3.162 agedur3 2.442 agedur4 2.283 agedur5 1.927 Results
Logit Regression Results Demographic age 237.053 age2 -309.685 age3 182.198 age4 -41.369 par1 2.078 par2 2.595 par3 2.161 pargt3 0.899 dur1 -3.974 dur2 -2.483 dur3 -1.661 dur4 -1.783 dur5 -1.540 Time yr2002 -0.457 yr2004 -0.427 yr2005 -1.473 yr2006 -0.111 timetrend 0.667 Economic fwage-1 -1.423 factivityrate-1 -0.971 Interest-1 0.244 Other catholic 0.169 constant -2.758 Education level01 constant 0.651 quality -2.003 timetrend -0.173 quality*tt 0.343 Demographic par0 -0.384 par1 -0.386 par2 -0.178 par3 -0.096 dur1 0.046 dur2 -0.234 dur3 -0.195 dur4 -0.091 dur5 -0.140 durgt5 -0.03 Education level 45 constant 1.438 quality -5.470 timetrend -0.145 quality*tt 0.702 interactions par0 -0.010 par1 0.258 par2 0.238 par3 0.094 dur1 0.138 dur2 0.484 dur3 0.468 dur4 0.557 dur5 0.394 durgt5 0.394 Demographic interactions agepar1 -1.420 agepar2 -2.663 agepar3 -2.441 agepargt3 -1.341 agedur1 3.512 agedur2 3.162 agedur3 2.442 agedur4 2.283 agedur5 1.927 The demographic profile of the base educational category is well determined with parity=0 and durgt5 base Results
Logit Regression Results Demographic age 237.053 age2 -309.685 age3 182.198 age4 -41.369 par1 2.078 par2 2.595 par3 2.161 pargt3 0.899 dur1 -3.974 dur2 -2.483 dur3 -1.661 dur4 -1.783 dur5 -1.540 Time yr2002 -0.457 yr2004 -0.427 yr2005 -1.473 yr2006 -0.111 timetrend 0.667 Economic fwage-1 -1.423 factivityrate-1 -0.971 Interest-1 0.244 Other catholic 0.169 constant -2.758 Education level01 constant 0.651 quality -2.003 timetrend -0.173 quality*tt 0.343 Demographic par0 -0.384 par1 -0.386 par2 -0.178 par3 -0.096 dur1 0.046 dur2 -0.234 dur3 -0.195 dur4 -0.091 dur5 -0.140 durgt5 -0.03 Education level 45 constant 1.438 quality -5.470 timetrend -0.145 quality*tt 0.702 interactions par0 -0.010 par1 0.258 par2 0.238 par3 0.094 dur1 0.138 dur2 0.484 dur3 0.468 dur4 0.557 dur5 0.394 durgt5 0.394 Demographic interactions agepar1 -1.420 agepar2 -2.663 agepar3 -2.441 agepargt3 -1.341 agedur1 3.512 agedur2 3.162 agedur3 2.442 agedur4 2.283 agedur5 1.927 Work and childbearing tend to be separate rather than combined activities; wage rate not significant although divided by quartiles; interest rate? Results
Logit Regression Results Demographic age 237.053 age2 -309.685 age3 182.198 age4 -41.369 par1 2.078 par2 2.595 par3 2.161 pargt3 0.899 dur1 -3.974 dur2 -2.483 dur3 -1.661 dur4 -1.783 dur5 -1.540 Time yr2002 -0.457 yr2004 -0.427 yr2005 -1.473 yr2006 -0.111 timetrend 0.667 Economic fwage-1 -1.423 factivityrate-1 -0.971 Interest-1 0.244 Other catholic 0.169 constant -2.758 Education level01 constant 0.651 quality -2.003 timetrend -0.173 quality*tt 0.343 Demographic par0 -0.384 par1 -0.386 par2 -0.178 par3 -0.096 dur1 0.046 dur2 -0.234 dur3 -0.195 dur4 -0.091 dur5 -0.140 durgt5 -0.03 Education level 45 constant 1.438 quality -5.470 timetrend -0.145 quality*tt 0.702 interactions par0 -0.010 par1 0.258 par2 0.238 par3 0.094 dur1 0.138 dur2 0.484 dur3 0.468 dur4 0.557 dur5 0.394 durgt5 0.394 Demographic interactions agepar1 -1.420 agepar2 -2.663 agepar3 -2.441 agepargt3 -1.341 agedur1 3.512 agedur2 3.162 agedur3 2.442 agedur4 2.283 agedur5 1.927 There is a fluctuating increase in the quantum of those 24 and over Results
Logit Regression Results Demographic age 237.053 age2 -309.685 age3 182.198 age4 -41.369 par1 2.078 par2 2.595 par3 2.161 pargt3 0.899 dur1 -3.974 dur2 -2.483 dur3 -1.661 dur4 -1.783 dur5 -1.540 Time yr2002 -0.457 yr2004 -0.427 yr2005 -1.473 yr2006 -0.111 timetrend 0.667 Economic fwage-1 -1.423 factivityrate-1 -0.971 Interest-1 0.244 Other catholic 0.169 constant -2.758 Education level01 constant 0.651 quality -2.003 timetrend -0.173 quality*tt 0.343 Demographic par0 -0.384 par1 -0.386 par2 -0.178 par3 -0.096 dur1 0.046 dur2 -0.234 dur3 -0.195 dur4 -0.091 dur5 -0.140 durgt5 -0.03 Education level 45 constant 1.438 quality -5.470 timetrend -0.145 quality*tt 0.702 interactions par0 -0.010 par1 0.258 par2 0.238 par3 0.094 dur1 0.138 dur2 0.484 dur3 0.468 dur4 0.557 dur5 0.394 durgt5 0.394 Demographic interactions agepar1 -1.420 agepar2 -2.663 agepar3 -2.441 agepargt3 -1.341 agedur1 3.512 agedur2 3.162 agedur3 2.442 agedur4 2.283 agedur5 1.927 For those from Northern Ireland Results
Logit Regression Results Demographic age 237.053 age2 -309.685 age3 182.198 age4 -41.369 par1 2.078 par2 2.595 par3 2.161 pargt3 0.899 dur1 -3.974 dur2 -2.483 dur3 -1.661 dur4 -1.783 dur5 -1.540 Time yr2002 -0.457 yr2004 -0.427 yr2005 -1.473 yr2006 -0.111 timetrend 0.667 Economic fwage-1 -1.423 factivityrate-1 -0.971 Interest-1 0.244 Other catholic 0.169 constant -2.758 Education level01 constant 0.651 quality -2.003 timetrend -0.173 quality*tt 0.343 Demographic par0 -0.384 par1 -0.386 par2 -0.178 par3 -0.096 dur1 0.046 dur2 -0.234 dur3 -0.195 dur4 -0.091 dur5 -0.140 durgt5 -0.03 Education level 45 constant 1.438 quality -5.470 timetrend -0.145 quality*tt 0.702 interactions par0 -0.010 par1 0.258 par2 0.238 par3 0.094 dur1 0.138 dur2 0.484 dur3 0.468 dur4 0.557 dur5 0.394 durgt5 0.394 Demographic interactions agepar1 -1.420 agepar2 -2.663 agepar3 -2.441 agepargt3 -1.341 agedur1 3.512 agedur2 3.162 agedur3 2.442 agedur4 2.283 agedur5 1.927 The differential quantum effect of education for those aged >23 in the 1957 – 77 cohort Results
Logit Regression Results Demographic age 237.053 age2 -309.685 age3 182.198 age4 -41.369 par1 2.078 par2 2.595 par3 2.161 pargt3 0.899 dur1 -3.974 dur2 -2.483 dur3 -1.661 dur4 -1.783 dur5 -1.540 Time yr2002 -0.457 yr2004 -0.427 yr2005 -1.473 yr2006 -0.111 timetrend 0.667 Economic fwage-1 -1.423 factivityrate-1 -0.971 Interest-1 0.244 Other catholic 0.169 constant -2.758 Education level01 constant 0.651 quality -2.003 timetrend -0.173 quality*tt 0.343 Demographic par0 -0.384 par1 -0.386 par2 -0.178 par3 -0.096 dur1 0.046 dur2 -0.234 dur3 -0.195 dur4 -0.091 dur5 -0.140 durgt5 -0.03 Education level 45 constant 1.438 quality -5.470 timetrend -0.145 quality*tt 0.702 interactions par0 -0.010 par1 0.258 par2 0.238 par3 0.094 dur1 0.138 dur2 0.484 dur3 0.468 dur4 0.557 dur5 0.394 durgt5 0.394 Demographic interactions agepar1 -1.420 agepar2 -2.663 agepar3 -2.441 agepargt3 -1.341 agedur1 3.512 agedur2 3.162 agedur3 2.442 agedur4 2.283 agedur5 1.927 The differential tempo effect of education for those aged >23 in the 1957 – 77 cohort Results
Marginal Effects For ith woman: Where is the vector of values of all the explanatory variables except for educ Educational variables are ordered: noqual base degree % sample 48 30 22 The marginal effect is taken as the mean of individual marginal effects over the particular category and the base Results
Marginal Effect of Education Parity 0 1 2 3 mean par at 24 No quals 0.043 0.084 0.039 0.033 0.98 others 0.066 0.132 0.049 0.037 0.51 Degree 0.069 0.193 0.073 0.050 0.10 Table: Probability of Birth 2001-7
Conclusions • The total marginal effect of educational attainment , including both quantum and tempo effects, is almost always positive • It peaks at 0.16 for women aged 33 with parity = 1 for the degree case; for parity = 0 the marginal effect is about one third of this • In the degree case the quantum effects are negative up to age 28 possibly reflecting the decline in degree ‘quality’ • For the poorly qualified the pattern is similar, except that the peak for parity = 1 is earlier, at 30 and smaller, at 0.11 • For most ages, the marginal effect is greater for parity 2 than 0 Results
Births and Birth Events In the analysis birth events rather than births per se are examined The data