Birth registration gaps by household wealth reveal differences that a national average can hide. The World Bank reports birth registration among children under five for five household wealth quintiles, from Q1 (the poorest 20%) to Q5 (the wealthiest 20%). This comparison matches all five quintiles for 105 countries. Within every country, Q1 through Q5 refer to the same survey year, which makes the within-country wealth gap directly comparable.
The central result is substantial. The median across the 105 country observations rises from 77.7% in Q1 to 95.2% in Q5. The median Q5-minus-Q1 gap is 9.7 percentage points. Fifty-two countries have a gap of at least 10 points, 39 have a gap of at least 20 points, and 12 have a gap of at least 40 points. Cross-country rankings still require caution because the country observation years range from 2006 to 2021.
Table of Contents
Q1 through Q5 use the same survey year within each country
This alignment is the main reason the five indicators are more useful together than as five separate articles. Pakistan uses 2018 for all quintiles, Nigeria uses 2013, and Mauritania uses 2021. The same pattern holds for all 105 matched countries. That means the wealth gradient can be calculated without mixing years inside a country. It does not mean that Pakistan in 2018 and Mauritania in 2021 form a same-year global ranking.
Q1 and Q5 are household wealth quintiles, not direct income quintiles. Household assets and housing characteristics are used to place households into relative wealth groups within the survey framework. The indicator measures the share of children under age five whose births are reported as registered with the relevant civil authority. It should not be treated as exactly the same measure as possession of a birth certificate.
The poorest and wealthiest quintiles have visibly different distributions
The Q1 median is 77.7%, with an interquartile range of 46.3% to 95.8%. 29 countries are below 50%, while 29 are at or above 95%. This wide distribution shows that birth registration among poorer households is close to universal in some countries but remains far from universal in others.
The Q5 median is 95.2%. Only 9 countries are below 50%, while 54 are at or above 95%. The contrast is not a comparison of rich countries with poor countries; it is a comparison of relatively poorer and wealthier household groups within each country.
In the largest-gap countries, Q5 exceeds Q1 by 40 to more than 60 points
| Country | Survey year | Q1 poorest 20% | Q5 wealthiest 20% | Q5−Q1 gap |
|---|---|---|---|---|
| Pakistan | 2018 | 9.3% | 76.0% | 66.7 pp |
| Mauritania | 2021 | 15.9% | 81.3% | 65.4 pp |
| Cameroon | 2018 | 30.5% | 92.4% | 61.9 pp |
| Sudan | 2014 | 37.0% | 97.9% | 60.9 pp |
| Nigeria | 2013 | 7.4% | 66.3% | 58.9 pp |
| Tanzania | 2016 | 7.7% | 65.1% | 57.4 pp |
| Zimbabwe | 2015 | 24.2% | 79.0% | 54.8 pp |
| Cote d’Ivoire | 2012 | 43.3% | 92.7% | 49.4 pp |
| Namibia | 2013 | 42.9% | 90.8% | 47.9 pp |
| Angola | 2016 | 9.6% | 54.9% | 45.3 pp |
Pakistan has the largest point gap in the matched data at 66.7 percentage points, followed by Mauritania at 65.4, Cameroon at 61.9, Sudan at 60.9 and Nigeria at 58.9. Tanzania and Zimbabwe also exceed 50 points. Pakistan provides a clear example of a full gradient: 9.3% in Q1, 27.3% in Q2, 44.2% in Q3, 63.4% in Q4 and 76.0% in Q5. Nigeria rises from 7.4% to 17.5%, 28.2%, 46.2% and 66.3% across the same five groups.
These differences establish that large wealth-related gaps were observed, but they do not identify the cause. Distance to registration offices, administrative procedures, fees, information, migration, conflict, and local service capacity may all matter. None of those mechanisms is measured by the five quintile indicators themselves, so the map should not be used to assign a single explanation to a country.
Looking at all five quintiles makes the gradient much easier to see
The country-level medians rise from Q1 77.7% to Q2 83.2%, Q3 89.4%, Q4 91.9% and Q5 95.2%. The unweighted means follow the same direction, from 67.5% in Q1 to 84.9% in Q5. These are distributions across countries, not a population-weighted global average.
The Q5-minus-Q1 gap is at least 10 points in 52 countries, at least 20 points in 39, and at least 40 points in 12. By contrast, 29 countries already have Q1 rates of 95% or more, leaving relatively little room for a large wealth gradient. Looking only at a national average would miss this distinction between broad coverage and unequal coverage.
A few point estimates run in the opposite direction, and that needs careful interpretation
In 8 of the 105 countries, the Q5 point estimate is lower than Q1. Gabon is 92.0% in Q1 and 85.7% in Q5, a −6.3-point difference, while Nepal is 58.1% and 54.1%, a −4.0-point difference. Several other reversals are less than about one percentage point.
These reversals do not prove that greater household wealth reduces birth registration. Quintile estimates come from survey samples and can be affected by sampling error, rounding, weighting and survey design. When rates are already close to 100%, tiny differences can also change the ordering of the quintiles. Large, repeated gaps are more informative than small decimal differences.
Country comparisons still need the observation year
The 105 country observations span 2006 through 2021. Nineteen use 2014, fourteen use 2012, ten use 2015 and another ten use 2016. Only India, Madagascar and Mauritania use 2021. The maps therefore show each country’s latest available observation in this dataset, not a 2021 or 2026 global league table.
The within-country comparison is stronger because all five quintiles share the same year. That is the main analytical advantage of consolidating the series: instead of publishing five near-duplicate pages, one page can show whether registration coverage reaches poorer households as well as wealthier households and where that internal gap is largest.
Data source and calculation
The analysis uses five World Bank World Development Indicators: SP.REG.BRTH.Q1.ZS, SP.REG.BRTH.Q2.ZS, SP.REG.BRTH.Q3.ZS, SP.REG.BRTH.Q4.ZS and SP.REG.BRTH.Q5.ZS. For each indicator, the latest non-empty observation was matched by country. The comparison then retained the 105 countries that have all five quintiles and verified that the observation year is identical across Q1 through Q5. The wealth gap is calculated as Q5 minus Q1 and is reported in percentage points.
The maps use a low-resolution world boundary for geographic context, so some small island states and separately reported areas may not appear as shaded polygons even though their statistics remain in the calculations. For current national policy assessment, the World Bank series should be checked alongside newer civil registration, health and national statistical sources where available.
Frequently Asked Questions
What do Q1 and Q5 mean in this dataset?
Q1 is the poorest 20% and Q5 the wealthiest 20% of households according to the survey wealth index. They are not direct income quintiles.
Can the 105 countries be ranked as if they were measured in the same year?
No. Country observation years range from 2006 to 2021. Within each country, however, Q1 through Q5 use the same survey year, so the wealth gap is internally consistent.
Why is Q5 sometimes lower than Q1?
Quintile values are survey estimates and can reflect sampling error, rounding, weighting and survey design. Small reversals should not be interpreted as evidence that higher wealth reduces birth registration.
Related Articles
These pages provide useful context for survey interpretation and broader population patterns without treating them as causes of birth registration differences.
- Tanzania 2022 Demographic and Health Survey guide
- Global population growth by country
- Global population density by country
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