How to measure migrations within France with the rolling census ?

1. How to measure migrations within France with the rolling census ?

2. Questions on migrations in the 2004 Census 3 questions • Place of residence at the 1st january 1999 (five years before) • Year of first coming in France (for people born out of France) • Year of last dwelling (only asked to the reference person of the household)

3. In the previous censuses • Place of residence at the 1st january of the year of the last census (1990 in the 1999 Census), since the 1962 Census • In 1999, the questions on the year of first coming in France and on the year of last dwelling were already asked • In 1990, these two questions were not asked

4. How to deal with the question on the place of residence before ? • Immigration • Emigration

5. Immigration In terms of place of present residence, the results for the question on place of residence before obtained with one collect are representative for each area covered in a representative way by the sampling frame: • Municipalities with less than 10000 inhabitants • Regions With a limit due to the census of institutionalized persons : in the municipalities with more than 10000 inhabitants, the annual sample of institutions is not representative.

6. Conclusion on immigration In representative areas, with the preceeding exception • The numbers of immigrants (from another area) and of non-migrants (same area than 5 year before) • The ratios of non-migrants and of immigration Can be calculated without bias.

7. Emigration Measuring the number of emigrants from an area is not so simple • To measure how many people emigrate form an area i to an area j, it is necessary that area j is fully enumerated, i.e. five years. • In deed, with one year, for an area i only those who emigrate to the municipalities of the area j which are enumerated that year, are observed. These municipalities may be non representative of the whole area j. • If area j is all a region, the number of emigrants from i is representative, because of the sampling frame.

8. General conclusion • To summarize, the matrix of migrations between regions can be established each year (but some cells can be unsignificant : out of more than 400 streams from i to j, only 90 are above 10000 ; the biggest is about 100000) • The totals of this matrix (emigrants and immigrants for each region) can be established each year • But we can not build each year a matrix using a more detailed geographical level than regions, for exemple departments or urban areas.

9. Peculiar cases • Taking in account an important stream to or from an area in a short time • For example, end of building a lot of individual houses in a small municipality • Consequences of an important migration during several years to a municipality • For example, in a suburb with increasing population due to immigration