french new census : news and utilization workshop on alternative methods for the census 4-6 july...

French new census : news and utilizationWorkshop on alternative methods for the census

4-6 july 2005 - Aguascalientes

Workshop on alternative methods for the census – Aguascalientes – 3 july 2005

Plan

Methodology overviewThe first new census surveys 2004 and 2005Methodology for estimationHow to use the data ? Some questions due to rolling surveys :

Age structureFlow dataMigrationEconomic data


Methodology overview


Francenumbers almost36 000 communesunder 10 000inhabitants (almost30 millionsinhabitants).These communesHave been spreadinto 5 groups

WHEN ?

WHO ?

HOW ?

HOW MUCH ?

Each year, in january and february

One group enumerated each year,More than 7 000 communes

Survey on every inhabitant of the communes of the group.In 2004, every inhabitants in the communes of first group,In 2005, every inhabitants in the communes of second group,etc.

Over 5 years, every inhabitant of the communes under 10 000 inhabitants is enumerated

Communes under 10 000 inhab.



› Five groups :–Regional representativity (population and dwellings)

› Each year :full enumeration in the communes of the group

› Including institutions


Balanced samples (Deville-Tillé)

› Number of dwellings

› Number of dwellings in collectives buildings

› Age groups and sex distribution– Less than 20 years old– 20-39– 40-59– 60-74– > 75– female– men

› Population of départements


A year for every commune

In 2009,we go on …

(exemple of Bas-Rhin)

"communes 2008" (less than 10 000 inhabitants)




"communes 2004« (less than 10 000 inhabitants)

Communes concernées chaque année(10 000 inhabitants or more)

Haguenau

Strasbourg

Sélestat

Saverne



France numbersalmost 900communes over 10 000inhabitants :near30 millionsinhabitants

WHEN ?

WHO ?

HOW ?

HOW MUCH ?

Every commune every year

Survey on a 8 % of the dwellings sample each year

Over 5 years, 40 % of the population issurveyed

Communes over 10 000 inhab.

Each year, in january and february


Large communes (> 10 000 inhab.)

› Dispatching buildings in 5 balanced groups fromthe inventory of located buildings (RIL)

› Each year, sampling addresses in the year-group to obtain 8 % of the whole commune’s dwellings

› Every dwelling of the sampled buildings are enumerated

› 40 % enumerated in 5 years› Special stratum for large addresses and new ones :

fully enumerated


A group of buildings sampled every year

In 2009,we go on …


Every year :

› Official population for every commune and administrative district

› Detailed statistical results :–At every geographical level

(micro data file for tabulation)

–Combining data collected during the 5 last years

–Relevant for the médium year (Y-2)

› Overall estimations at national and regional level : based on data collected the last year


The first surveys of the new census in 2004 and 2005


First surveys 2004 and 2005

A successfull operation : good coopération with the communes survey well accepted by the population fast exploitation : results published at the end of the year

Low non response rate : Non surveyed dwellings (impossible to contact (including

some vacant dwellings), long time absence, refusal) :

Benefits of annualization confirmed : Linked to the diminution ot the volume : recruitment, training… Ability to improve the process : many improvements

2004>2005, technical process, instructions, cost managment


Survey 2004 : dissemination

January 2005 : Population estimates :

France and regions Communes :

communes < 10 000 habitants enumerated in 2004 a hundred of big cities (with the first 8% sample)

Main characteristics of population and dwellings in France :

Evolution since 1999 National level publication

July 2005 : Key figures : France, regions, communes < 10

000 and big cities Regional publications


Methodology for estimation


Population estimates : communes > 10 000

› Every year Y : pop. estimate for Y-2

› 8% sample every year Y

› Mobile sum of data collected during 5 latest years(Y-4 <-> Y)

› Weighted according to the average number of dwellings ~ number of dwellings Y-2


Population estimates : communes < 10 000

› Every year Y : population estimates for Y-2 :–using extrapolation based on local tax file (evolution

of the number of dwellings) : for communes enumerated in Y-4 and Y-3

–census data for communes enumerated in Y-2

–using linear interpolation for communes enumerated in Y-1 and Y

› Data may be weighted according to the Y-2 estimate


How to estimate population of communes < 10 000 inhab. in Y-2 ?

Y-5 Y-4 Y-3 Y-2 Y-1 Y

I

II

III

IV

V

2AIIIR

5AVR

4AIR

3AIIR

1AIVR

AVR

2~ AIR

2~ AIIR

2~ AIVR

2~ AVR


Use of the data


Use of the new census data

› General census : a snapshot every 9 years› New census : not a movie, rather a slide show

– communes < 10 000 inhab. : more frequent full enumeration

– communes > 10 000 inhab. :sample survey, but annual update :

‐ Suburban districts evolution

› Any level :annual update

› Working party with users to elaborate examples and recommandations for use


The annual survey

› Use for results at a national and regional level :–Example : results of the 2004 survey

› Use to calibrate cumulated data :–The annual survey gives a dated information vs

period information for cumulated data


Use of the cumulated data

› Detailed results at any geographical level

› Communes over 10 000 inh. :–Mobile average Y-2

› Communes under 10 000 inh. :–Enumerated one time during Y-4 <–> Y period

–Two weights :‐Weight according to the year of their enumeration

‐Weight according to their population estimate for Y-2


Some questions about the different dates of enumerations

› What about age ?

› What about flow data : e.g. commuters ?

› What about migration ?

› What about economic data ?


Questions of age structure


Problems for comparisons

› Data are collected at different dates (between Y-4 and Y), how to compare them ?

› First, consider the reference date is Y-2 : medium year of the period. The data are never distant more than 2 years

›Correct or not correct ? That is the question !


Age/Generation

0,000

0,200

0,400

0,600

0,800

1,000

1,200

1,400

1,600

1 6 11 16 21 26 31 36 41 46 51 56 61 66 71 76 81 86 91 96

1999

2004


Age/Generation

› Age structure : correction possible with the national ratio

› Example : %60-74 years old :–Compare communes enumerated year Y-i (i = 0 to 4)

–Estimate (%60-74commune)Y-2

–Coefficient kN-i = (%60-74France)Y-2/(%60-74France)Y-i

– (%60-74commune)Y-2 = (%60-74commune)Y-i*k

› Rem : Communes > 10 000 inh. : moving average relevant for Y-2


Example : communes in Touraine

Amboise Azay-le-Rideau Bléré Bourgeuil Château-Renault Fondettes Chinon Nazelles Loches

Year >10 000 Y-4 Y-4 Y-3 Y-4 Y-3 Y-2 Y Y-4Population 11 461 3 106 4 578 4 108 5 481 8 918 8 918 3 635 6 329%60-74 observed 15,24 15,84 15,90 16,29 14,09 12,92 12,92 17,00 17,35%60-74 N-2 true 15,24 16,13 15,44 16,43 13,96 13,19 12,92 16,86 16,29Obs-True 0,00 -0,29 0,46 -0,15 0,13 -0,27 0,00 0,14 1,06k 1,0000 1,0066 1,0066 1,0057 1,0066 1,0057 1,0000 0,9753 1,0066%60-74 N-2 estimated 15,24 15,94 16,01 16,38 14,18 12,99 12,92 16,58 17,46Estimate-True 0,00 -0,19 0,56 -0,05 0,22 -0,19 0,00 -0,28 1,17


Explaination

› Correction is not effective :–Age structure of commune may be very different

from national one. E.g : Loches

0,00

0,20

0,40

0,60

0,80

1,00

1,20

1,40

1,60

1,80

0 a

n

7 a

ns

14

an

s

21

an

s

28

an

s

35

an

s

42

an

s

49

an

s

56

an

s

63

an

s

70

an

s

77

an

s

84

an

s

91

an

s

98

an

s

Loches

France


Multi-communes area age structure

› Simply add the different communes, even they are enumerated different years

› Consider result is relevant for year Y-2› Consider the weight of large communes (> 10 000

inh.). Estimates for those communes are moving averages relevant for Y-2 :

–E.g. : Conurbations, Employment areas…, large communes weight often > 50%

› Because correction using models, may be worse


Questions of flow data :the example of commuters


Example : commuters

Urban area of Montpellier :

- 380 000 inhab.

- 45 000 surveyed every year


Workers coming from 3 communes

2004 20142008 20182010 20122006 2016

< 10 000 enumerated in 2004 < 10 000 enumerated in 2006 > 10 000 (8% every year)

2020



2004 20142008 20182010 20122006 2016


2020

?? ?

?



2004 20142008 20182010 20122006 2016


2020


Questions of migrations


Migration (I) – migration balance for a commune or a group of communes

› Former general census :– Mig90-99 = Pop99 - Pop90 - Birth90-99+ Deaths90-99

– But suppose that the two censuses are strictly comparable (direct migration balance estimate only at the national level : see Desplanques)

› New rolling census :– Population estimate for Y-2 :

‐ Moving average for communes > 10 000 inh.‐ Estimate using administrative data (evolution of the number of dwellings in the local tax file) for communes < 10 000 inh.

– MigY-7..Y-2 = PopY-2 – PopY-7 - BirthY-7..Y-2+ DeathsY-7..Y-2

– Same methodology for the different annual surveys– Balance over 5 years to cover a complet census cycle– Comparison between different communes


Migration (II) – migration flows for a commune

› Commune A enumerated in Y : –Knowledge of flows from other communes over the last

5 years (question « Where did you live 5 years ago ? »)

–What about the flows from A to other communes ?‐To large communes : average over 5 years‐To small ones : depend on their census year


Questions of economic data


Correction for economic situation

› Unemployment rate linked to the economic situation => results may be affected during a 5 years period

› Correction using the annual survey› E.g. : comparing unemployment rates among

communes in a labour market area–Compare communes (c and d) unemployment ratios

relative to France the same year :

kYFrance

kYdcom

iYFrance

iYccom

unemp

unempto

unemp

unemp

%

%

%

% ..


Conclusion : Use for local comparisons

› Data are relevant for the year Y-2› For major characteristic : slow trends, no problem

for comparison› For more fluctuating data : use of the annual

survey :–E.g : compare unemployment relative exposure for a

commune to the country at the same year

–Compare relative exposures between communes enumerated at different years


Any questions…

french new census : news and utilization workshop on alternative methods for the census 4-6 july...

Documents