Homogamy and heterogamy in sub-Saharan Africa: Implications for couples’ fertility behaviour

Figures & data

Table 1. Percent distribution of the study population by selected characteristics of couples.

Characteristic	Nigeria (n = 3 185)	Zambia (n = 3 175)	Ghana (n = 1785)
CEB
0–4	34.7	23.2	46.3
5+	65.3	76.8	53.7
Education
Both have none	23.5	2.7	15.4
Husband more	26.4	38.2	37.9
Wife more	13.7	8.3	7.4
Both secondary/higher	23.9	14.3	36.3
Both primary	12.5	36.5	3.0
Occupation
Not same	67.2	61.2	56.1
Whitecollar	5.7	2.2	2.9
Sales and services	13.2	6.4	6.8
Agriculture	–	28.3	31.0
Manual and others	–	1.9	3.2
Agriculture and others	3.9	–	–
Age
Same	3.2	3.3	4.1
Wife older	4.5	5.4	8.5
Wife 1–4 years younger	25.2	32.9	30.9
Wife 5–9 years younger	42.2	40.2	33.5
Wife 10+ years younger	24.9	18.2	23.0
Religion
Both Catholic	8.8	17.6	9.1
Both other Christian	44.7	75.3	64.6
Both Muslim	36.7	–	10.9
Both traditionalist	4.0	–	3.7
Wife Catholic/husband other Christian	2.1	4.2	2.9
Wife Christian/husband Muslim, traditionalist and other	3.7	2.9	8.8
Ethnicity
Inter-ethnic	11.6	45.0	18.4
Same ethnic group	88.4	55.0	81.6
Place of residence
Urban	42.0	38.4	44.9
Rural	58.0	61.6	55.1
Household wealth
Poorest	18.6	18.2	16.3
Poorer	15.4	19.2	20.1
Middle	16.7	20.4	17.7
Richer	19.0	20.4	19.2
Richest	30.3	21.8	26.7
Fertility preference
Both no more	26.1	55.6	50.9
Both want or undecided	45.4	16.3	24.3
Wife wants or undecided/husband no more	9.9	10.4	11.1
Wife no more/husband wants or undecided	18.6	17.7	13.7
Marital status
Married	98.6	99.5	91.5
Living together with partner	1.4	0.5	8.5

Table 2. Mean CEB by selected couples’ characteristics.

Characteristic	Nigeria	Zambia	Ghana
	Mean CEB (standard deviation)
Mean CEB
2001–2	–	6.8 (2.8)	–
2003	6.6 (2.9)	–	5.3 (2.3)
2007	–	6.4 (2.6)	–
2008	5.9 (2.8)	–	4.6 (2.2)
2013	5.3 (2.5)	–	–
2014	–	–	4.5 (2.1
2013–14	–	6.2 (2.5)	–
Pooled data	5.7 (2.7)	6.3 (2.6)	4.8 (2.2)
Education
Both have none	7.4 (2.9)	6.5 (3.1)	6.0 (2.0)
Husband more	5.9 (2.5)	6.4 (2.6)	5.1 (2.3)
Wife more	5.0 (2.5)	5.9 (2.3)	4.9 (2.0)
Both secondary/higher	4.1 (2.0)	4.8 (2.3)	4.1 (1.9)
Both primary	5.9 (2.4)	7.0 (2.4)	6.3 (2.1)
Occupation
Not same	5.9 (2.7)	6.2 (2.5)	4.5 (2.1)
Whitecollar	3.8 (2.0)	3.7 (2.0)	3.5 (1.1)
Sales and services	5.3 (2.7)	5.4 (2.4)	4.0 (2.1)
Agriculture	–	7.2 (2.5)	6.0 (2.1)
Manual and others	–	5.8 (2.5)	4.1 (2.0)
Agriculture and others	6.3 (2.6)	–	–
Age
Same	5.2 (2.7)	5.8 (2.6)	4.5 (2.6)
Wife older	5.5 (3.0)	5.2 (2.5)	4.8 (2.3)
Wife 1–4 years younger	5.4 (2.7)	6.3 (2.6	4.7 (2.2)
Wife 5–9 years younger	5.8 (2.7)	6.7 (2.5)	5.2 (2.1)
Wife 10 years younger	6.2 (2.8)	6.3 (2.6)	5.1 (2.3)
Religion
Both Catholic	5.2 (2.7)	6.7 (2.5)	5.1 (2.2)
Both other Christian	5.0 (2.3)	6.4 (2.5)	4.7 (2.2)
Both Muslim	6.7 (2.9)	–	5.3 (2.1)
Both traditionalist	7.2 (3.0)	–	6.2 (2.3)
Wife Catholic/husband other Christian	5.4 (2.2)	6.2 (2.7)	4.8 (2.0)
Wife Christian/husband Muslim, traditional or other	5.5 (2.7)	5.8 (2.4)	5.4 (2.1)
Ethnicity
Inter-ethnic	5.6 (2.7)	5.9 (2.6)	4.7 (2.3)
Same ethnic group	5.7 (2.7)	6.7 (25)	5.1 (2.2)

Table 3. Poisson regression models estimating the IRR for CEB and homogamous and heterogamous characteristics of couples in Nigeria, Zambia and Ghana.

Characteristic	IRR (95% confidence interval)
	Nigeria	Zambia	Ghana
Education
Both have none (RC)	1.00	1.00	1.00
Husband more	0.95 (0.90–1.00)^†	1.07 (0.96–1.21)	0.93 (0.88–0.98)*
Wife more	0.86 (0.81–0.92)***	1.02 (0.90–1.15)	0.92 (0.85–0.98)*
Both secondary/higher	0.80 (0.75–0.85)***	0.95 (0.84–1.08)	0.83 (0.79–0.88)***
Both primary	0.93 (0.88–0.99)*	1.11 (0.98–1.24)^†	1.05 (0.96–1.14)
Occupation
Not same (RC)	1.00	1.00	1.00
Whitecollar	0.86 (0.80–0.92)***	0.78 (0.68–0.88)***	0.92 (0.84–1.01)^†
Sales and services	1.01 (0.96–1.06)	0.95 (0.89–1.02)	1.01 (0.93–1.10)
Agriculture	–	1.03 (1.00–1.06)*	1.07 (1.03–1.12)**
Manual and others	–	1.00 (0.89–1.11)	1.00 (0.90–1.11)
Agriculture and others	0.98 (0.94–1.03)	–	–
Age
Same (RC)	1.00	1,00	1.00
Wife older	0.98 (0.88–1.10)	0.92 (0.83–1.03)	1.06 (0.95–1.19)
Wife 1–4 years younger	0.98 (0.91–1.07)	1.02 (0.94–1.12)	1.05 (0.96–1.16)
Wife 5–9 years younger	1.01 (0.93–1.09)	1.07 (0.98–1.17)	1.12 (1.02–1.23)*
Wife 10+ years younger	1.00 (0.92–1.09)	1.00 (0.91–1.10)	1.09 (0.99–1.20)^†
Religion
Both Catholic (RC)	1.00	1.00	1.00
Both other Christian	1.01 (0.95–1.07)	0.99 (0.96–1.02)	0.97 (0.92–1.03)
Both Muslim	1.20 (1.12–1.28)***	–	1.13 (1.05–1.21)**
Both traditionalist	1.08 (0.89–1.32)	–	1.06 (0.97–1.17)
Wife Catholic/husband other Christian	1.06 (0.96–1.17)	0.95 (0.88–1.02)	0.95 (0.86–1.05)
Wife Christian/husband Muslim, traditional or other	1.09 (0.99–1.21)^†	0.92 (0.84–1.00)^†	0.99 (0.92–1.07)
Ethnicity
Inter-ethnic (RC)	1.00	1.00	1.00
Same ethnic group	1.02 (0.97–1.07)	1.07 (1.04–1.10)***	1.02 (0.97–1.07)
Fertility preference
Both no more (RC)	1.00	1.00	1.00
Both want or undecided	0.72 (0.69–0.74)***	0.67 (0.64–0.70)***	0.62 (0.58–0.65)***
Wife wants or undecided/husband no more	0.81 (0.76–0.86)***	0.76 (0.72–0.80)***	0.78 (0.74–0.83)***
Wife no more/husband wants of undecided	0.90 (0.86–0.94)***	0.87 (0.83–0.90)***	0.81 (0.77–0.85)***
Place of residence
Urban (RC)	1.00	1.00	1.00
Rural	1.05 (1.01–1.10)**	1.01 (0.98–1.06)	1.01 (0.96–1.06)
Household wealth
Poorest (RC)	1.00	1.00	1.00
Poorer	0.94 (0.89–0.99)*	0.97 (0.93–1.01)	0.96 (0.91–1.06)
Middle	0.91 (0.86–0.96)**	0.95 (0.92–0.99)*	0.95 (0.89–1.01)
Richer	0.84 (0.80–0.89)***	0.86 (0.81–0.90)***	0.78 (0.72–0.84)***
Richest	0.68 (0.64–0.73)***	0.75 (0.70–0.80)***	0.64 (0.59–0.70)***

***p < 0.001.

**p < 0.01.

*p < 0.05.

^†p < 0.10.