In general, survival occurs when a unit is active and identifiable both before and after a specific (business) demographic event. The unit may be changed in some way, e.g. in terms of economic activity, size, ownership or location, but there should be continuity of the unit reference number in the statistical business register. In the Business Demography context, survival occurs if an enterprise is active in terms of employment and/or turnover in the year of birth and the following year(s). An enterprise is also considered to have survived if the linked legal unit(s) have ceased to be active, but their activity has been taken over by a new legal unit set up specifically to take over the factors of production of that enterprise (= survival by take-over)."