IAOS-OECD conference "Better statistics for better lives",19-21 September 2018, Paris. More information at: http://www.oecd.org/IAOS2018/

1. Regional &
Urban Policy
Applying the degree of
urbanisation to the globe:
A new harmonised definition reveals a
different picture of global urbanisation
IAOS Conference, Better Statistics for Better Lives, OECD, Paris
Session 6D, 14:00 to 15:30 21 September 2018
Presented by Lewis Dijkstra, Lewis.Dijkstra@ec.europa.eu
Head of the Economic Analysis Sector
DG for Regional and Urban Policy

2. Why is a global definition needed?
• To compare urbanisation across countries
• To understand the speed, scale and impact of
global urbanisation
• To compare cities in a reliable manner
• To collect UN Sustainable Development Goals
indicators for cities, urban and rural areas in a
way that can be compared across countries and
continents

3. SDG City goals, but no city definition
City
Centre
Edge of
the city
Open Space Low High
Air pollution High Low
Access to transport High Low
Built-up area per head Low High
Population change Low (neg) High
Built-up change Low High

4. 20
30
40
50
60
70
80
90
100
0 5 10 15 20 25 30
%ofpopulation
km from city centre
Access to public transport by distance to centre
Praha
Berlin
London
Madrid
Paris

5. Two main points
• National definitions are too different to be used
for international comparisons
• The degree of urbanisation produces plausible
classifications and different results in terms of
global urbanisation levels.

6. The well known narrative…
• The world is 50% urban.
• Middle income countries are less urbanised.
• Low income countries are least urbanised.
• Urbanisation will grow rapidly in low-income
countries between 2010 and 2050.
… is purely based on
national definitions

7. A single density threshold cannot
reproduce the nationally defined urban
population shares

8. National definitions vary and are
often not statistical
• 75 countries use
population size or
density, but
thresholds and
spatial units vary
• 47 use a
combination of
population and
other indicators
• 10 use other
indicators than
population
• 100 countries use
administrative
designations, not a
statistical definition
that can be
replicated in other
countries

9. 85 countries out of 103 use a
minimum population of 5,000 or less
0
5
10
15
20
25
30
35
0
5,000
10,000
15,000
20,000
25,000
30,000
35,000
40,000
45,000
50,000
55,000
60,000
65,000
70,000
75,000
80,000
85,000
90,000
95,000
100,000
Numerofcountries
Population size thresholds
Population size thresholds to define urban population, WUP 2018
Japan
China
Mali

10. Developing a global, people-based
definition of cities and settlements
• Degree of urbanisation and functional urban area
definition developed for the EU & OECD 2011
• Voluntary commitment Habitat III in 2016
• Supported by EU, FAO, OECD, UN-Habitat, WB
• Side events at UN Stats Com 2017 & 2018
• Presentation UN Stats Com 2019 for info
• Presentation UN Stats Com 2020 for decision
• Special sessions at ERSA 2019 and 2020

11. Why a people-based definition?
• People capture the main characteristics
• Cities: the potential of people to interact
• Rural areas: How to provide services in a areas
with a low population density
• Agglomeration economies and scale economies
are about people, not buildings, not nightlights
• Historically, land use maps were the most
spatially disaggregated data source. But they
don’t tell you how many people live in a location.
• But built-up land per capita differs too much
between countries and changes over time.

12. Two definitions with a common
element: Cities
Cities
Towns &
suburbs
Rural
areas
Commuting
zones
Non-metro
areas
Degree of
urbanisation
Functional
urban area

13. Three types of grid cells
Urban
centres
Contiguous cells
above 1,500 residents per km2 and
at least 50,000 people in the centre
Urban
Clusters
Contiguous cells
above 300 residents per km2 and
at least 5,000 people in the cluster
Rural
grid cells
Cells below 300 residents per km2 +
other cells outside urban clusters

14. Cork, Ireland: Urban centre,
urban clusters and rural grid cells

15. Three types of local units
Cities > 50% pop. in urban centres
Towns and
suburbs
> 50% pop. in urban clusters
and not classified as city
Rural area > 50% pop. in rural grid cells
Urban areas = Cities + Towns and Suburbs

16. Cork, Ireland: Urban centre,
urban clusters and rural grid cells

17. Cork, Ireland: City, towns & suburbs,
and rural areas

18. 0
10
20
30
40
50
60
70
80
90
100
NorthernAfrica
MiddleAfrica
EasternAfrica
WesternAfrica
SouthernAfrica
EasternAsia
WesternAsia
CentralAsia
South-EasternAsia
SouthernAsia
NorthernAmerica
CentralAmerica
Caribbean
SouthAmerica
NorthernEurope
WesternEurope
EasternEurope
SouthernEurope
Oceania
World
Shareofpopulation,in%
Population in nationally defined urban areas and by
degree of urbanisation, 2015
Rural areas Towns & suburbs Cities ND Urban area
Two different concepts of urban:
Large only vs small and large

19. Urban areas … lost in translation?
Small urban areas
• Medium density
• Medium population
• Medium share of
agricultural jobs
• Some services
(primary school,
doctor)
• Europe & Americas
Large urban areas
• High Density
• Big population
• Low shares of
agricultural jobs
• Specialised services
(higher education,
hospital, government)
• Africa & Asia

20. More agreement on large cities
0
10
20
30
40
50
60
NorthernAfrica
MiddleAfrica
EasternAfrica
WesternAfrica
SouthernAfrica
EasternAsia
WesternAsia
CentralAsia
South-EasternAsia
SouthernAsia
NorthernAmerica
CentralAmerica
Caribbean
SouthAmerica
NorthernEurope
WesternEurope
EasternEurope
SouthernEurope
Oceania
World
Shareoftotalpopulation,in%
Population in cities, national definitions and degree of
urbanisation, 2015
Urban centre >300,000 pop Urban centre 50,000-300,000 pop Nationally defined cities >300,000 pop

21. 92% (99%) of the population of
nationally defined cities matches an
urban centre of 300,000+ (all UCs)
0
10
20
30
40
50
60
70
80
90
100
NorthernAfrica
MiddleAfrica
EasternAfrica
WesternAfrica
SouthernAfrica
EasternAsia
WesternAsia
CentralAsia
South-EasternAsia
SouthernAsia
NorthernAmerica
CentralAmerica
Caribbean
SouthAmerica
NorthernEurope
WesternEurope
EasternEurope
SouthernEurope
Oceania
World
Shareofpopulationinnationallydefindedcitiesthatmatch,
in%
Population in nationally defined cities and urban centres, 2015
an urban centre >300,000 pop an urban centre 50,000-300,000 pop

22. 89% of the population of urban
centres of 300k+ matches a city
0
10
20
30
40
50
60
70
80
90
100
NorthernAfrica
MiddleAfrica
EasternAfrica
WesternAfrica
SouthernAfrica
EasternAsia
WesternAsia
CentralAsia
South-EasternAsia
SouthernAsia
NorthernAmerica
CentralAmerica
Caribbean
SouthAmerica
NorthernEurope
WesternEurope
EasternEurope
SouthernEurope
Oceania
World
Shareofpopulation,in%
Urban centres over 300,000 inhabitants that match a
nationally defined city

23. But a lot of uncertainty remains
Cities
Towns &
suburbs
Rural
areas
Cities
Towns &
suburbs
Rural
areas
Cities
Towns &
suburbs
Rural areas
Population
weighted
average size
Average
size
Northern Africa 58 32 10 48 22 29 -10 -9 19 3,628 5,512
Middle Africa 55 24 20 23 17 61 -33 -7 40 10,400 11,954
Eastern Africa 39 40 21 14 28 59 -25 -12 38 1,684 1,697
Western Africa 47 31 22 25 25 51 -23 -6 29 1,634 2,218
Southern Africa 43 30 27 41 28 31 -1 -3 4 692 752
Eastern Asia 45 38 17 42 36 23 -3 -3 6 145 197
Western Asia 59 26 15 41 26 33 -18 0 18 5,360 3,629
Central Asia 37 45 19 15 39 46 -22 -5 27 23,998 28,271
South-Eastern Asia 46 34 20 35 33 33 -12 -1 13 1,408 1,851
Southern Asia 52 34 14 29 49 22 -23 15 9 956 852
Northern America 48 24 27 48 24 28 0 0 1 1 2
Central America 53 26 21 48 22 30 -5 -4 9 144 97
Caribbean 46 38 16 38 31 31 -8 -7 15 292 277
South America 57 26 17 50 22 28 -7 -4 11 939 1,154
Northern Europe 47 29 24 46 28 26 -1 -1 2 146 173
Western Europe 35 33 32 33 32 34 -1 -1 2 90 31
Eastern Europe 39 30 32 35 23 42 -4 -6 10 5,649 3,481
Southern Europe 39 34 27 38 32 30 -1 -2 3 94 42
Oceania 48 29 23 35 26 39 -13 -3 16 1,095 1,218
World 48 33 19 36 34 30 -13 1 12 1,610 2,601
Population share according to
GHS Pop in %
Population share according to
World Pop in %
Difference in degree of urbanisation using
World pop and GHS pop, in % points
CIESIN census units in
sq km

24. Conclusions
• National definitions of urban areas are too
different to be suitable for international
comparisons
• The degree of urbanisation produces very similar
population shares in cities over 300,000
• The share of population in rural areas varies from
identical to radically different, but part of the
difference is due to data uncertainty
• More population data with a high spatial
resolution is needed
• This definition will be further tested and
discussed.

25. More information
• https://ec.europa.eu/eurostat/cros/content/globa
l-city-and-settlement-definition_en
• http://ghsl.jrc.ec.europa.eu/degurba.php
• Free global population grid 1975-2015
• http://ghsl.jrc.ec.europa.eu/datasets.php
• Nice visualisation of global
data:http://luminocity3d.org/WorldPopDen/
• Visualisation of the European data:
http://ec.europa.eu/regional_policy/mapapps/urb
an/degurba.html