French new census : news and utilization Workshop on alternative methods for the census 4-6 july Aguascalientes

Workshop on alternative methods for the census – Aguascalientes – 3 july 2005 Plan  Methodology overview  The first new census surveys 2004 and 2005  Methodology for estimation  How to use the data ?  Some questions due to rolling surveys :  Age structure  Flow data  Migration  Economic data

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

Workshop on alternative methods for the census – Aguascalientes – 3 july 2005 France numbers almost communes under inhabitants (almost 30 millions inhabitants). These communes Have been spread into 5 groups WHEN ? WHO ? HOW ? HOW MUCH ? Each year, in january and february One group enumerated each year, More than 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 inhabitants is enumerated Communes under inhab.

Workshop on alternative methods for the census – Aguascalientes – 3 july 2005 Communes under inhab. › Five groups : –Regional representativity (population and dwellings) › Each year : full enumeration in the communes of the group › Including institutions

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

Workshop on alternative methods for the census – Aguascalientes – 3 july 2005 A year for every commune In 2009, we go on … (exemple of Bas-Rhin) "communes 2006" (less than inhabitants) Haguenau Strasbourg Sélestat Saverne Communes under inhab.

Workshop on alternative methods for the census – Aguascalientes – 3 july 2005 France numbers almost 900 communes over inhabitants : near 30 millions inhabitants 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 is surveyed Communes over inhab. Each year, in january and february

Workshop on alternative methods for the census – Aguascalientes – 3 july 2005 Large communes (> inhab.) › Dispatching buildings in 5 balanced groups from the 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

Workshop on alternative methods for the census – Aguascalientes – 3 july 2005 A group of buildings sampled every year In 2009, we go on …

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

Workshop on alternative methods for the census – Aguascalientes – 3 july 2005 The first surveys of the new census in 2004 and 2005

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

Workshop on alternative methods for the census – Aguascalientes – 3 july 2005 Survey 2004 : dissemination  January 2005 :  Population estimates :  France and regions  Communes :  communes < 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 < and big cities  Regional publications

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

Workshop on alternative methods for the census – Aguascalientes – 3 july 2005 Population estimates : communes > › 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

Workshop on alternative methods for the census – Aguascalientes – 3 july 2005 Population estimates : communes < › 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

Workshop on alternative methods for the census – Aguascalientes – 3 july 2005 How to estimate population of communes < inhab. in Y-2 ? Y-5Y-4Y-3Y-2Y-1Y I II III IV V

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

Workshop on alternative methods for the census – Aguascalientes – 3 july 2005 Use of the new census data › General census : a snapshot every 9 years › New census : not a movie, rather a slide show –communes < inhab. : more frequent full enumeration –communes > inhab. : sample survey, but annual update : ‐ Suburban districts evolution › Any level : annual update › Working party with users to elaborate examples and recommandations for use

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

Workshop on alternative methods for the census – Aguascalientes – 3 july 2005 Use of the cumulated data › Detailed results at any geographical level › Communes over inh. : –Mobile average Y-2 › Communes under 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

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

Workshop on alternative methods for the census – Aguascalientes – 3 july 2005 Questions of age structure

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

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

Workshop on alternative methods for the census – Aguascalientes – 3 july 2005 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 (%60-74 commune ) Y-2 –Coefficient k N-i = (%60-74 France ) Y-2 /(%60-74 France ) Y-i –(%60-74 commune ) Y-2 = (%60-74 commune ) Y-i *k › Rem : Communes > inh. : moving average relevant for Y-2

Workshop on alternative methods for the census – Aguascalientes – 3 july 2005 Example : communes in Touraine

Workshop on alternative methods for the census – Aguascalientes – 3 july 2005 Explaination › Correction is not effective : –Age structure of commune may be very different from national one. E.g : Loches

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

Workshop on alternative methods for the census – Aguascalientes – 3 july 2005 Questions of flow data : the example of commuters

Workshop on alternative methods for the census – Aguascalientes – 3 july 2005 Example : commuters Urban area of Montpellier : inhab surveyed every year

Workshop on alternative methods for the census – Aguascalientes – 3 july 2005 Workers coming from 3 communes < enumerated in 2004< enumerated in 2006> (8% every year) 2020

Workshop on alternative methods for the census – Aguascalientes – 3 july 2005 Workers coming from 3 communes < enumerated in 2004< enumerated in 2006> (8% every year) 2020 ? ? ? ?

Workshop on alternative methods for the census – Aguascalientes – 3 july 2005 Workers coming from 3 communes < enumerated in 2004< enumerated in 2006> (8% every year) 2020

Workshop on alternative methods for the census – Aguascalientes – 3 july 2005 Workers coming from 3 communes < enumerated in 2004< enumerated in 2006> (8% every year) 2020

Workshop on alternative methods for the census – Aguascalientes – 3 july 2005 Workers coming from 3 communes < enumerated in 2004< enumerated in 2006> (8% every year) 2020

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

Workshop on alternative methods for the census – Aguascalientes – 3 july 2005 Migration (I) – migration balance for a commune or a group of communes › Former general census : –Mig = Pop 99 - Pop 90 - Birth Deaths –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 > inh. ‐ Estimate using administrative data (evolution of the number of dwellings in the local tax file) for communes < inh. – Mig Y-7..Y-2 = Pop Y-2 – Pop Y-7 - Birth Y-7..Y-2 + Deaths Y-7..Y-2 – Same methodology for the different annual surveys – Balance over 5 years to cover a complet census cycle – Comparison between different communes

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

Workshop on alternative methods for the census – Aguascalientes – 3 july 2005 Questions of economic data

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

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

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