In Sweden, for example, a school reform which allowed independent schools to select students by ability led to a marked increase in segregation across schools by immigrant status (Bjorklund et al., In Denmark, for example, research suggests that since public school choice was introduced in the 1990s, segregation has increased because native students tend to choose schools with fewer immigrant and low-SES students (Bloem and Diaz, 2007). Rangvid (2007b) shows that native Danes tend to “opt out” of local schools when the proportion of migrants is between 35 and 40%.