Classification of socioeconomic status Socioeconomic status of the victim was assumed according to their zip code in correlation with a data adjustment with Statistics Austria, Vienna, Austria. The 23 districts of Vienna were subdivided in three groups: rich, middle class, and poor, according to data from Statistics Austria and government reports. Rich was defined as > 110% of average income; middle class 90-110% of average income; and poor <90% of average income; Districts for "rich" were considered: 1., 4., 7., 13., 18., 19., 23.; Middle class: 2., 3., 6., 9., 11., 14., 17., 21., 22.; Poor: 5., 10., 12., 15., 16., 20.; Outcome measurement The primary outcome measured was the association between migration background and IPV.