1. 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

2. 2 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

3. Overview3 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

4. 4 Total Births Age Specific Fertility Rates Fertility in Northern Ireland

5. Education and fertility5 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

6. Education and fertility6 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

7. The NILS7 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

8. The NILS8 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

9. The data9 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

10. The data10 Sources of Information available for the NILS Fertility Panel 101 Census 91 4,653 7,019 Census 01 GRO BSO 61,263 24,041 32,960 530 26,710

11. The data11 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 Women 157,277 100.0

12. The data12 Educational Qualifications 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

13. The data13 The Distribution of Educational Attainment

14. The data14 Source: 2001 Census Distribution of Educational Attainment by Year that Woman was aged 24

15. The data15 Women in the Labour Market Source: DETINI

16. The data16 Mean Age of Mother at Time of Birth

17. The Statistical Model17 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

18. The Statistical Model18 The Logit Model EDUCATION includes interactions with PARITY, DURATION and TIME so demographic profile can vary with educational attainment TIME captures the change in quantum for women aged > 23

19. Results19 Demographic age 237.053 age 2 -309.685 age 3 182.198 age 4 -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 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 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 Logit Regression Results 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 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

20. Results20 Demographic age 237.053 age 2 -309.685 age 3 182.198 age 4 -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 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 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 Logit Regression Results 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 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 The demographic profile of the base educational category is well determined with parity=0 and durgt5 base

21. Results21 Work and childbearing tend to be separate rather than combined activities; wage rate not significant although divided by quartiles; interest rate? Demographic age 237.053 age 2 -309.685 age 3 182.198 age 4 -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 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 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 Logit Regression Results 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 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

22. Results22 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 There is a fluctuating increase in the quantum of those 24 and over Demographic age 237.053 age 2 -309.685 age 3 182.198 age 4 -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 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 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 Logit Regression Results 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

23. Results23 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 For those from Northern Ireland Demographic age 237.053 age 2 -309.685 age 3 182.198 age 4 -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 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 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 Logit Regression Results 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

24. Results24 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 The differential quantum effect of education for those aged >23 in the 1957 – 77 cohort Demographic age 237.053 age 2 -309.685 age 3 182.198 age 4 -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 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 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 Logit Regression Results 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

25. Results25 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 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 The differential tempo effect of education for those aged >23 in the 1957 – 77 cohort Demographic age 237.053 age 2 -309.685 age 3 182.198 age 4 -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 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 Logit Regression Results 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

26. Results26 Marginal Effects Where is the vector of values of all the explanatory variables except for educ For ith woman: Educational variables are ordered: noqual basedegree % sample483022 The marginal effect is taken as the mean of individual marginal effects over the particular category and the base

27. 27 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 Marginal Effect of Education

28. Results28 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

29. Results29 Parity Proportions by Age and Education

30. The data30 Births and Birth Events In the analysis birth events rather than births per se are examined