German Office for Migration and Refugees publishes survey comparing immigrants with and without German citizenship

The German Federal Office for Migration and Refugees has recently published a survey on the naturalisation behaviour of foreign residents in Germany and the effects of citizenship acquisition. Here is a summary of the main results:
 
Young people under 30 decide more often to naturalize, while older people make less use of this possibility. However, when taking into account other factors, age proves to have a minor influence on the decision to acquire citizenship.
 
Immigrants without German citizenship have less often German citizens in their families than citizens or persons in the naturalisation process. A large proportion of the Optionspflichtige (persons who have acquired German citizenship by birth in the territory and are required to renounce a foreign citizenship until age 23 in order to retain their German one) have relatives with German citizenship in their families.
 
Taking into account different dimensions and indicators of integration, it appears that naturalised immigrants are much better integrated than non-naturalised ones. Optionspflichtige are as well integrated as naturalised migrants and in some dimensions their inclusion in the German society is even stronger.
 
Naturalised immigrants often have a higher degree of education (58 %) than non-naturalised ones (35 %) and than persons in the naturalisation process (40 %).
 
Although the four investigated groups are linguistically well integrated in Germany, Optionspflichtige and naturalised immigrants speak slightly better German than non-naturalised persons and those in the process of naturalising. This order is reversed for skills in the language of a country of origin. The non-naturalised use their language of origin more often that the other groups.
 
Indicators regarding the identification dimension of integration show that non-naturalised immigrants consider Germany less often as the centre of their lives than naturalised immigrants and persons in the naturalisation process.
 
Read the full text of the report (in German)