What is a population projection?
A population projection is an estimation of a future population. It is based on past trends, as well as assumptions about the future levels of the three main determinants of population growth: fertility, mortality and migration.
INSEE has produced the latest demographic projections using the 2018 population census and the 2017 to 2019 civil registry files. They cover metropolitan France and the 5 Overseas departments (DOM). 3 types of projections have been provided by INSEE:
- Population projections: these projections are based on the latest known population size by sex and age, and they simulate, for each year of the projection period, the number of men and women by age based on assumptions about future changes to the three main determinants of population growth (fertility, mortality and migration).
- Household projections (forthcoming): these are estimations of the number of households, which are primarily used to estimate future housing demands. The population projections serve as the starting point and they are then coupled with assumptions about changes to cohabitation behaviour.
- Labour force projections (forthcoming): these are based on the population projections, as well as the assumptions about labour force participation in the future; they attempt to understand future trends regarding the labour force (number of economically active individuals) available for economic production, based on various scenarios concerning demographic changes and behaviours related to labour market participation.
What is Omphale?
Omphale is an application that consists of a theoretical population projection model, demographic databases, demographic analysis techniques and predictive modelling tools. The 2022 Omphale model provides population projections by sex and age, for every year up until 2070, for all zones with at least 50 000 inhabitants and made up of whole municipalities. Labour force and household projections can also be obtained via the model by simply using the sex and age rates for the projected populations (labour force participation rate and head of household rate). Omphale 2022 allows users to incorporate a variety of assumptions that are purely demographic in nature since they are based on fertility, mortality and migration.
The Omphale 2022 projections are constructed via the following 3 steps:
- Constituting the zones:
This involves defining the zones to be used for the projections, i.e., aggregating municipal or supra-municipal zones. The application already comes with “standard” zoning; this means that regions (the old and 2016 versions), departments and the 2010 employment areas are already pre-defined in the application.
- Selecting a scenario:
A scenario is a set of assumptions on fertility, mortality and/or net migration. 11 scenarios (whose assumptions are detailed below) are pre-defined in Omphale. Users are able to view the INSEE projections as 2 different products or versions:
- the “light” version (P1) contains 3 scenarios: the “middle” scenario and the 2 extreme scenarios (“high population” / “low population”)
- the “full” version (P2) contains all 11 scenarios (the standard “middle,” “high population,” “low population,” “high fertility,” “low fertility,” “high life expectancy,” “low life expectancy,” “high migration,” “low migration,” “young population” and "elderly population" scenarios), of which 3 of them are also available in the “light” version.
Projections at sub-departmental geographical levels are systematically calibrated to the departmental projections.
Which scenarios are pre-defined in Omphale?
The 2022 fertility, mortality and migration quotients are calculated for a given zone. Thereafter, they change in line with the national level, extending the latest fertility and mortality trends. Internal migration quotients, however, are kept constant. These projections cannot be considered as forecasts, since probabilities cannot be attached to the different scenarios.
|Situtation in 2020||Middle scenario||Low scenario||High scenario||Working assumption|
|Total fertility rate||1.83 children per woman||1.80 children as of 2022||1.60 children as of 2030||2.00 children as of 2030||1.50 children as of 2030|
|Average age at childbirth||30.8 years||33.0 years as of 2052|
|Years as of Life expectancy at birth, women||85.1 years||90.0 years as of 2070||86.5 years as of 2070||93.5 years as of 2070||85.6 years as of 2021|
|Life expectancy at birth, men||79.1 years||87.5 years as of 2070||84 years as of 2070||91.0 years as of 2070||79.7 years as of 2021|
|Annual net migration||+70 000 per year||+70 000 per year||+20 000 per year||+120 000 per year||0 per year|
The different scenarios are based on the following assumptions:
For the middle scenario, a target fertility rate (to be achieved by 2023) of 1.80 children was adopted. (This is a significant change from the 2016 exercise, where a much higher target, 1.95 children, was used).
Compared to the 2016 exercise, the gap between the middle scenario and the high and low scenarios has increased from +/-0.15 to +/-0.20. The total fertility rate for the low scenario is 1.60 and 2.00 for the high scenario, which is slightly below the replacement level.
To account for the pandemic, specific assumptions (shared by all the scenarios) have been adopted for 2020 and 2021, which are based on recent data: the total fertility rate was raised from 1.83 in 2020 to 1.79 in 2021 and 1.80 in 2022.
Compared with previous projections, these new projections reduce life expectancy at birth in 2070 for women (-3.0 years) and men (-2.6 years). In 2070, life expectancy at birth is 90.0 years for women and 87.5 years for men.
For the high life expectancy scenario, life expectancies at birth are 3.5 years higher than those for the middle scenario. Similarly, for the low scenario, they are 3.5 years lower than those for the middle scenario.
These downward changes are due to the increased uncertainty linked to the pandemic, as well as the recent slowdown in the rise in life expectancy, which may or may not continue in the future.
The middle scenario for net migration has been maintained at +70 000 per year, as in the previous exercise; the low scenario has been set at +20 000 per year and the high scenario at +120 000 per year. As the aforementioned uncertainty also applies to the year 2021, the high and low versions are reached as early as 2021 in scenarios that use them.
The 11 scenarios defined in Omphale and the 2 projection versions proposed by INSEE are the following:
|Scenarios||Selected assumption||Different versions|
|Fertility||Life expectancy||Migration||Light (P1)||Full (P2)|
|High life expectancy||Constant||High||Constant||Yes|
|Low life expectancy||Constant||Low||Constant||Yes|
|Low migrations||Constant||Middle||Low||Yes||Young population||High||Low||High||Yes||Elderly population||Low||High||Low||Yes|
By allowing several scenarios to be applied to a single projection, impartiality is preserved. Moreover, by offering the two extreme scenarios ( high and low population), which complement the middle scenario, the prospective dimension of the tool can be assured.
How are the projections defined and obtained?
To request a projection, the researcher must submit a formal request via the Quetelet-Progedo-Diffusion Data Request Platform (référence APF-0003).
To obtain their desired projection, the researcher must provide the following information in their request:
- the type of projection desired ((choice between individuals, households or working population). As a reminder, only population projections are currently available
- the zones to be used (exact selection of municipal or supra-municipal zones to be aggregated, with a minimum of 50 000 inhabitants within a given defined and continuous zone). Please note that "standard" zoning is also available, i.e., France (metropolitan), one or more regions, one or more departments and one or more ZE 2010. If a zone is composed of multiple municipalities (a non-standard zone), all the municipality codes for the zone must be provided (exactly 5 characters). If there are several zones, a code and a label must be provided in order to clearly identify each zone.
- the scenarios and selected assumptions to be used (choice between 2 products: light version (P1) with 3 scenarios or full version (P2) with 11 scenarios.
Once a request has been validated and approved, INSEE will produce the requested projection and send the results to Adisp, who will in turn forward them to the researcher.
For population projections, five “results” files per scenario are produced. These files pertain to the population (available for each year of the projection period),
births, deaths, natural population changes and net migration (available for every step of the projection).
As for labour force and household projections, only one “results” file per scenario is produced. This file pertains to the number of workers or the number of households (available for each year of the projection period).
The INSEE documentation
Tip: Before making a request, explore the various free products already being offered by INSEE. They are all open access and downloadable via their website (studies, publications and detailed results about the projections on the 11 scenarios at the national, regional and departmental levels).