Seasonal Adjustment of monthly enterprises'creations

The enterprises and institutions inter-administrative list's daily management entrusted to the INSEE since 1973 represents an unique source in order to follow in a cyclical way ­ in consideration of the necessary precautions when using any administrative source to measure an economic phenomenon ­ the creation of any sort of enterprises. The creation monitoring has lately been the subject of a thorough revision in order to harmonize on the European level annual statistics - the latter being generally the observable ones apart from having a tool like the French list at one's disposal. The series, which have been being monthly published in France for about fifteen years, have themselves been reviewed so as to rely on coherent definitions for the newly harmonized annual series. The new device has been established since mid-February 2007 with the publishing of January 2007 statistics enclosed with «retropoled» series since 1993. These works comprised a significant panel dedicated to the correcting of monthly series' seasonal variations which is the subject of the hereby working document. The thought process is greatly original for many reasons:  Not only were raw data sensitive to economic fluctuations but also to some phenomena of administrative origin or to the behaviour of economic agents.  For reasons linked to the general operation timetable, the method choice was based in 2006 on the study of former creating series.  Wide use of data analysis methods (PC, HCM) helped to make this choice  The possibility of introducing new seasonal adjustment tools in these analysis in order to compare the effect with those tested in 2006. At the conclusion of this work and by taking into account the imposed limiting factors, a method turn out to answer all the necessary criteria. The chosen correcting seasonal variations' method is the one which is being at the present time used when publishing every month enterprises' creations in